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TEST BANK for Physics for Scientists and Engineers: A Strategic Approach, 3rd Edition by Randall D. Knight (Chs. 1-42)

TABLE OF CONTENTS Chapter 1 Concepts of Motion Chapter 2 Kinematics in One Dimension Chapter 3 Vectors and Coordinate Systems Chapter 4 Kinematics in Two Dimensions Chapter 5 Force and Motion Chapter 6 Dynamics I: Motion Along a Line Chapter 7 Newton's Third Law Chapter 8 Dynamics II: Motion in a Plane Chapter 9 Impulse and Momentum Chapter 10 Energy Chapter 11 Work Chapter 12 Rotation of a Rigid Body Chapter 13 Newton's Theory of Gravity Chapter 14 Oscillations Chapter 15 Fluids and Elasticity Chapter 16 A Macroscopic Description of Matter Chapter 17 Work, Heat, and the First Law of Thermodynamics Chapter 18 The Micro/Macro Connection Chapter 19 Heat Engines and Refrigerators Chapter 20 Traveling Waves Chapter 21 Superpositions

Chapter 22 Wave Optics Chapter 23 Ray Optics Chapter 24 Optical Instruments Chapter 25 Electric Charges and Forces Chapter 26 The Electric Field Chapter 27 Gauss's Law Chapter 28 The Electric Potential Chapter 29 Potential and Field Chapter 30 Current and Resistance Chapter 31 Fundamentals of Circuits Chapter 32 The Magnetic Field Chapter 33 Electromagnetic Induction Chapter 34 Electromagnetic Fields and Waves Chapter 35 AC Circuits Chapter 36 Relativity Chapter 37 The Foundations of Modern Physics Chapter 38 Quantization 38.1 Conceptual Questions Chapter 39 Wave Functions and Uncertainty Chapter 40 One-Dimensional Quantum Mechanics Chapter 41 Atomic Physics Chapter 42 Nuclear Physics

Full Test Bank for Physics for Scientists and Engineers, 3e (Knight) Chapter 1 Concepts of Motion 1.1 Conceptual Questions 1) The current definition of the standard meter of length is based on A) the distance between the earth's equator and north pole. B) the distance between the earth and the sun. C) the distance traveled by light in a vacuum. D) the length of a particular object kept in France. Answer: C Var: 1 2) The current definition of the standard second of time is based on A) the frequency of radiation emitted by cesium atoms. B) the earth's rotation rate. C) the duration of one year. D) the oscillation of a particular pendulum kept in France. Answer: A Var: 1 3) The current definition of the standard kilogram of mass is based on A) the mass of the earth. B) the mass of the sun. C) the mass a particular object kept in France. D) the mass of a cesium-133 atom. Answer: C Var: 1 4) If a woman weighs 125 lb, her mass expressed in kilograms is x kg, where x is A) less than 125. B) greater than 125. Answer: A Var: 1 5) If a tree is 15 m tall, its height expressed in feet is x ft, where x is A) less than 15. B) greater than 15. Answer: B Var: 1 6) If a flower is 6.5 cm wide, its width expressed in millimeters is x mm, where x is A) less than 6.5. B) greater than 6.5. Answer: B Var: 1 1 Copyright © 2013 Pearson Education, Inc.

7) If an operatic aria lasts for 5.75 min, its length expressed in seconds is x s, where x is A) less than 5.75. B) greater than 5.75. Answer: B Var: 1 8) Scientists use the metric system chiefly because it is more accurate than the English system. A) True B) False Answer: B Var: 1 9) When adding two numbers, the number of significant figures in the sum is equal to the number of significant figures in the least accurate of the numbers being added. A) True B) False Answer: B Var: 1 10) When determining the number of significant figures in a number, zeroes to the left of the decimal point are never counted. A) True B) False Answer: B Var: 1 1.2 Problems 1) Convert 1.2 × 10-3 to decimal notation. A) 1.200 B) 0.1200 C) 0.0120 D) 0.0012 E) 0.00012 Answer: D Var: 5 2) Write out the number 7.35 × 10-5 in full with a decimal point and correct number of zeros. A) 0.00000735 B) 0.0000735 C) 0.000735 D) 0.00735 E) 0.0735 Answer: B Var: 5

3) 0.0001776 can also be expressed as A) 1.776 × 10-3. B) 1.776 × 10-4. C) 17.72 × 104. D) 1772 × . 7 E) 177.2 × 10 . Answer: B Var: 5 4) 0.00325 × 10-8 cm can also be expressed in mm as A) 3.25 × 10-12 mm. B) 3.25 × 10-11 mm. C) 3.25 × 10-10 mm. D) 3.25 × 10-9 mm. E) 3.25 × 10-8 mm. Answer: C Var: 1 5) If, in a parallel universe, π has the value 3.14149, express π in that universe to four significant figures. A) 3.141 B) 3.142 C) 3.1415 D) 3.1414 Answer: A Var: 1 6) The number 0.003010 has A) 7 significant figures. B) 6 significant figures. C) 4 significant figures. D) 2 significant figures. Answer: C Var: 1 7) What is

to the proper number of significant figures?

A) 0.91 B) 0.911 C) 0.9108 D) 0.9 Answer: A Var: 50+

8) What is the value of π(8.104)2, written with the correct number of significant figures? A) 206.324 B) 206.323 C) 206.3 D) 206 E) 200 Answer: C Var: 1 9) What is the sum of 1123 and 10.3 written with the correct number of significant figures? A) 1.13 × 103 B) 1133.3000 C) 1.1 × 103 D) 1133.3 E) 1133 Answer: E Var: 1 10) What is the sum of 1.53 + 2.786 + 3.3 written with the correct number of significant figures? A) 8 B) 7.6 C) 7.62 D) 7.616 E) 7.6160 Answer: B Var: 3 11) What is the difference between 103.5 and 102.24 written with the correct number of significant figures? A) 1 B) 1.3 C) 1.26 D) 1.260 E) 1.2600 Answer: B Var: 3 12) What is the product of 11.24 and 1.95 written with the correct number of significant figures? A) 22 B) 21.9 C) 21.92 D) 21.918 E) 21.9180 Answer: B Var: 3

22) A weight lifter can bench press 171 kg. How many milligrams (mg) is this? A) 1.71 × 108 mg B) 1.71 × 109 mg C) 1.71 × 107 mg D) 1.71 × 106 mg Answer: A Var: 50+ 23) How many nanoseconds does it take for a computer to perform one calculation if it performs 6.7 x 107 calculations per second? A) 15 ns B) 67 ns C) 11 ns D) 65 ns Answer: A Var: 50+ 24) The shortest wavelength of visible light is approximately 400 nm. Express this wavelength in centimeters. A) 4 × 10-5 cm B) 4 × 10-7 cm C) 4 × 10-9 cm D) 4 × 10-11 cm E) 400 × 10-11 cm Answer: A Var: 1 25) The wavelength of a certain laser is 0.35 micrometers, where 1 micrometer = 1 x 10-6 m. Express this wavelength in nanometers. A) 3.5 × 102 nm B) 3.5 × 103 nm C) 3.5 × 101 nm D) 3.5 × 104 nm Answer: A Var: 50+ 26) A certain CD-ROM disk can store approximately 6.0 × 102 megabytes of information, where 106 bytes = 1 megabyte. If an average word requires 9.0 bytes of storage, how many words can be stored on one disk? A) 6.7 × 107 words B) 5.4 × 109 words C) 2.1 × 107 words D) 2.0 × 109 words Answer: A Var: 9 7 Copyright © 2013 Pearson Education, Inc.

27) A plot of land contains 5.8 acres. How many square meters does it contain? [1 acre = 43,560 ft2] A) 2.3 × 104 m2 B) 7.1 × 103 m2 C) 7.0 × 104 m2 D) 5.0 × 104 m2 Answer: A Var: 50+ 28) A person on a diet loses 1.6 kg in a week. How many micrograms/second (µg/s) are lost? A) 2.6 × 103 μg/s B) 1.6 × 105 μg/s C) 44 μg/s D) 6.4 × 104 μg/s Answer: A Var: 11 29) Albert uses as his unit of length (for walking to visit his neighbors or plowing his fields) the albert (A), the distance Albert can throw a small rock. One albert is 92 meters. How many square alberts is equal to one acre? (1 acre = 43,560 ft2 = 4050 m2) Answer: 1.29 A2 Var: 50+ 30) Convert a speed of 4.50 km/h to units of ft/min. (1.00 m = 3.28 ft) A) 0.246 ft/min B) 82.3 ft/min C) 165 ft/min D) 246 ft/min E) 886 ft/min Answer: D Var: 1 31) The exhaust fan on a typical kitchen stove pulls 600 CFM (cubic feet per minute) through the filter. Given that 1.00 in. = 2.54 cm, how many cubic meters per second does this fan pull? A) 0.283 m3/sec B) 0.328 m3/sec C) 3.05 m3/sec D) 32.8 m3/sec Answer: A Var: 1

32) The mass of a typical adult woman is closest to A) 20 kg. B) 35 kg. C) 75 kg. D) 150 kg. Answer: C Var: 1 33) The height of the ceiling in a typical home, apartment, or dorm room is closest to A) 100 cm. B) 200 cm. C) 400 cm. D) 500 cm. Answer: B Var: 1 34) Approximately how many times does an average human heart beat in a year? A) 4 × 105 B) 4 × 106 C) 4 × 107 D) 4 × 108 E) 4 × 109 Answer: C Var: 1 35) Approximately how many times does an average human heart beat in a lifetime? A) 3 × 1011 B) 3 × 1010 C) 3 × 109 D) 3 × 108 E) 3 × 107 Answer: C Var: 1 36) Approximately how many pennies would you have to stack to reach an average 8-foot ceiling? A) 2 × 102 B) 2 × 103 C) 2 × 104 D) 2 × 105 E) 2 x 106 Answer: B Var: 1

37) Estimate the number of times the earth will rotate on its axis during a human's lifetime. A) 3 × 104 B) 3 × 105 C) 3 × 106 D) 3 × 107 E) 3 x 108 Answer: A Var: 1 38) Estimate the number of pennies that would fit in a box one foot long by one foot wide by one foot tall. A) 5 × 102 B) 5 × 103 C) 5 × 104 D) 5 × 105 E) 5 x 106 Answer: C Var: 1 39) A marathon is 26 mi and 385 yd long. Estimate how many strides would be required to run a marathon. Assume a reasonable value for the average number of feet/stride. A) 4.5 × 104 strides B) 4.5 × 103 strides C) 4.5 × 105 strides D) 4.5 × 106 strides Answer: A Var: 1 40) The period of a pendulum is the time it takes the pendulum to swing back and forth once. If the only dimensional quantities that the period depends on are the acceleration of gravity, g, and the length of the pendulum, ℓ, what combination of g and ℓ must the period be proportional to? (Acceleration has SI units of m ∙ s-2.). A) g/ℓ B) gℓ2 C) gℓ D) E) Answer: E Var: 1

41) The speed of a wave pulse on a string depends on the tension, F, in the string and the mass per unit length, μ, of the string. Tension has SI units of kg · m · s-2 and the mass per unit length has SI units of What combination of F and μ must the speed of the wave be proportional to? A) F / μ B) μ / F C) D) E) Answer: A Var: 1 42) The position x, in meters, of an object is given by the equation x = A + Bt + Ct2, where t represents time in seconds. What are the SI units of A, B, and C? A) m, m, m B) m, s, s C) m, s, s2 D) m, m/s, m/s2 E) m/s, m/s2, m/s3 Answer: A Var: 1

Physics for Scientists and Engineers, 3e (Knight) Chapter 2 Kinematics in One Dimension 2.1 Conceptual Questions 1) If the acceleration of an object is negative, the object must be slowing down. A) True B) False Answer: B Var: 1 2) If the graph of the position as a function of time for an object is a horizontal line, that object cannot be accelerating. A) True B) False Answer: A Var: 1 3) If an object is accelerating toward a point, then it must be getting closer and closer to that point. A) True B) False 11 Copyright © 2013 Pearson Education, Inc.

Answer: B Var: 1 4) When can we be certain that the average velocity of an object is always equal to its instantaneous velocity? A) always B) never C) only when the velocity is constant D) only when the acceleration is constant E) only when the acceleration is changing at a constant rate Answer: C Var: 1 5) Suppose that an object is moving with constant nonzero acceleration. Which of the following is an accurate statement concerning its motion? A) In equal times its speed changes by equal amounts. B) In equal times its velocity changes by equal amounts. C) In equal times it moves equal distances. D) A graph of its position as a function of time has a constant slope. E) A graph of its velocity as a function of time is a horizontal line. Answer: B Var: 1

6) Suppose that a car traveling to the west (the -x direction) begins to slow down as it approaches a traffic light. Which statement concerning its acceleration in the x direction is correct? A) Both its acceleration and its velocity are positive. B) Both its acceleration and its velocity are negative. C) Its acceleration is positive but its velocity is negative. D) Its acceleration is negative but its velocity is positive. Answer: C Var: 1 7) The motion of a particle is described in the velocity versus time graph shown in the figure. We can say that its speed

A) increases. B) decreases. C) increases and then decreases. D) decreases and then increases. Answer: D Var: 1 8) The motions of a car and a truck along a straight road are represented by the velocity-time graphs in the figure. The two vehicles are initially alongside each other at time t = 0. At time T, what is true about these two vehicles since time t = 0?

A) The truck will have traveled further than the car. B) The car will have traveled further than the truck. C) The truck and the car will have traveled the same distance. D) The car will be traveling faster than the truck. Answer: A Var: 1

9) The graph in the figure shows the position of an object as a function of time. The letters H-L represent particular moments of time. At which moments shown (H, I, etc.) is the speed of the object (a) the greatest? (b) the smallest?

Answer: (a) J (b) I Var: 1 10) The figure shows the position of an object (moving along a straight line) as a function of time. Assume two significant figures in each number. Which of the following statements about this object is true over the interval shown?

A) The object is accelerating to the left. B) The object is accelerating to the right. C) The acceleration of the object is in the same direction as its velocity. D) The average speed of the object is 1.0 m/s. Answer: A Var: 1

11) The figure shows the graph of the position x as a function of time for an object moving in the straight line (the x-axis). Which of the following graphs best describes the velocity along the x-axis as a function of time for this object?

Answer: D Var: 1

12) An object is moving with constant non-zero acceleration along the +x-axis. A graph of the velocity in the x direction as a function of time for this object is A) a horizontal straight line. B) a vertical straight line. C) a straight line making an angle with the time axis. D) a parabolic curve. Answer: D Var: 1

14) An object starts its motion with a constant velocity of 2.0 m/s toward the east. After 3.0 s, the object stops for 1.0 s. The object then moves toward the west a distance of 2.0 m in 3.0 s. The object continues traveling in the same direction, but increases its speed by 1.0 m/s for the next 2.0 s. Which graph below could represent the motion of this object? A)

Answer: D Var: 1 15) The figure shows the velocity of a particle as it travels along the x-axis. What is the direction of the acceleration at t = 0.5 s?

A) in the +x direction B) in the -x direction C) The acceleration is zero. Answer: B Var: 1

16) The figure represents the velocity of a particle as it travels along the x-axis. At what value (or values) of t is the instantaneous acceleration equal to zero?

A) t = 0 B) t = 0.5 s and t = 2 s C) t = 1 s Answer: C Var: 1 17) A ball is thrown directly upward and experiences no air resistance. Which one of the following statements about its motion is correct? A) The acceleration of the ball is upward while it is traveling up and downward while it is traveling down. B) The acceleration of the ball is downward while it is traveling up and upward while it is traveling down. C) The acceleration is downward during the entire time the ball is in the air. D) The acceleration of the ball is downward while it is traveling up and downward while it is traveling down but is zero at the highest point when the ball stops. Answer: C Var: 1 18) Two objects are thrown from the top of a tall building and experience no appreciable air resistance. One is thrown up, and the other is thrown down, both with the same initial speed. What are their speeds when they hit the street? A) The one thrown up is traveling faster. B) The one thrown down is traveling faster. C) They are traveling at the same speed. Answer: C Var: 1

19) Two objects are dropped from a bridge, an interval of 1.0 s apart, and experience no appreciable air resistance. As time progresses, the DIFFERENCE in their speeds A) increases. B) remains constant. C) decreases. D) increases at first, but then stays constant. E) decreases at first, but then stays constant. Answer: B Var: 1 20) Which one of the following graphs could possibly represent the vertical position as a function of time for an object in free fall? A)

Answer: D Var: 1 2.2 Problems 1) A cat runs along a straight line (the x-axis) from point A to point B to point C, as shown in the figure. The distance between points A and C is 5.00 m, the distance between points B and C is 10.0 m, and the positive direction of the x-axis points to the right. The time to run from A to B is 20.0 s, and the time from B to C is 8.00 s. As the cat runs along the x-axis between points A and C (a) what is the magnitude of its average velocity? (b) what is its average speed?

Answer: (a) 0.179 m/s Var: 1

(b) 0.893 m/s

2) The figure shows the position of an object as a function of time. During the time interval from time t = 0.0 s and time t = 9.0 s, (a) what is the length of the path the object followed? (b) what is the displacement of the object?

Answer: (a) 5.0 m Var: 1

(b) 1.0 m

3) As part of an exercise program, a woman walks south at a speed of 2.00 m/s for 60.0 minutes. She then turns around and walks north a distance 3000 m in 25.0 minutes (a) What is the woman's average velocity during her entire motion? A) 0.824 m/s south B) 1.93 m/s south C) 2.00 m/s south D) 1.79 m/s south E) 800 m/s south (b) What is the woman's average speed during her entire motion? A) 0.824 m/s B) 1.93 m/s C) 2.00 m/s D) 1.79 m/s E) 800 m/s Answer: (a) A (b) C Var: 1

4) The figure shows the position of an object as a function of time, with all numbers accurate to two significant figures. Between time t = 0.0 s and time t = 9.0 s, (a) what is the average speed of the object? (b) what is the average velocity of the object?

Answer: (a) 0.56 m/s Var: 1

(b) 0.11 m/s

5) If the fastest you can safely drive is 65 mi/h what is the longest time you can stop for dinner if you must travel 541 m in 9,6 h total? A) 1.0 h B) 1.3 h C) 1.4 h D) You can't stop at all. Answer: B Var: 50+ 6) Arthur and Betty start walking toward each other when they are 100 m apart. Arthur has a speed of 3.0 m/s and Betty has a speed of 2.0 m/s. Their dog, Spot, starts by Arthur's side at the same time and runs back and forth between them at 5.0 m/s. By the time Arthur and Betty meet, what distance has Spot run? Answer: 100 m Var: 1 7) A racing car accelerates uniformly from rest along a straight track. This track has markers spaced at equal distances along it from the start, as shown in the figure. The car reaches a speed of 140 km/h as it passes marker 2. Where on the track was the car when it was traveling at 70 km/h?

8) The figure represents the position of a particle as it travels along the x-axis. Between t = 2 s and t = 4 s, what is (a) the average speed of the particle and (b) the average velocity of the particle?

Answer: (a) 1.0 m/s Var: 1

(b) 0.00 m/s

9) The figure shows a graph of the velocity as a function of time for a basketball player traveling up and down the court in a straight-line path. for the 10 s shown on the graph, find (a) the net displacement of the player. (b) the total distance run by the player.

Answer: (a) 18 m Var: 1

(b) 20 m

10) The position of an object as a function of time is given by x =bt2 - ct, where b = 2.0 m/s2 and c = 6.7 m/s, and x and t are in SI units. What is the instantaneous velocity of the object when t = 2.2? A) 1.7 m/s B) 2.1 m/s C) 2.3 m/s D) 2.7 m/s Answer: B Var: 22

11) The position of an object is given by where and x and t are in SI units. What is the instantaneous acceleration of the object when A) -13 m/s2 B) 2.9 m/s2 C) 4.6 m/s2 D) 13 m/s2 Answer: D Var: 36 12) The velocity of an object as a function of time is given by v(t) = 2.00 m/s + (3.00 m/s) t - (1.0 m/s2) t2. Determine the instantaneous acceleration of the object at time t = 5.00 s. A) -8.00 m/s2 B) -7.00 m/s2 C) 2.00 m/s2 D) 0.00 m/s2 E) -2.00 m/s2 Answer: B Var: 5 13) The position of an object as a function of time is given by

where

c = 60 m/s and d = 7.0 m. (a) Find the instantaneous acceleration at t =2.4 s. (b) Find the average acceleration over the first 2.4 seconds. Answer: (a) 44 m/s2 (b) 18 m/s2 Var: 1 14) The velocity of an object is given by the expression v(t) = 3.00 m/s + (4.00 m/s3)t2, where t is in seconds. Determine the position of the object as a function of time if it is located at x = 1.00 m at time t = 0.000 s. A) (4.00 m/s)t + 1.00 m B) (3.00 m/s)t + (1.33 m/s3)t3 C) (4.00 m/s)t D) 1.33 m E) 1.00 m + (3.00 m/s)t + (1.33 m/s3)t3 Answer: E Var: 5

15) The acceleration of an object as a function of time is given by a(t) = (3.00 m/s3)t, where t is in seconds. If the object is at rest at time t = 0.00 s, what is the velocity of the object at time t = 6.00 s? A) 18.0 m/s B) 54.0 m/s C) 0.00 m/s D) 15.0 m/s E) 108 m/s Answer: B Var: 5 16) The acceleration of an object as a function of time is given by a(t) = (3.00 m/s3)t, where t is in seconds. If the object has a velocity 1.00 m/s at time t = 1.00 s, what is the displacement of the object between time t = 2.00 s and time t = 4.00 s? A) 33.0 m B) 30.0 m C) 36.0 m D) 27.0 m Answer: D Var: 1 17) A car accelerates from 10.0 m/s to 30.0 m/s at a rate of 3.00 m/s2. How far does the car travel while accelerating? A) 80.0 m B) 133 m C) 226 m D) 399 m Answer: B Var: 50+ 18) A dragster starts from rest and travels 1/4 mi in 6.70 s with constant acceleration. What is its velocity when it crosses the finish line? A) 296 mi/h B) 269 mi/h C) 188 mi/h D) 135 mi/h Answer: B Var: 40 19) A airplane that is flying level needs to accelerate from a speed of 2.00 × 102 m/s to a speed of 2.40 × 102 m/s while it flies a distance of 1.20 km. What must be the acceleration of the plane? A) 4.44 m/s2 B) 2.45 m/s2 C) 7.33 m/s2 D) 5.78 m/s2 E) 1.34 m/s2 Answer: C Var: 1 28 Copyright © 2013 Pearson Education, Inc.

20) A runner maintains constant acceleration after starting from rest as she runs a distance of 60.0 m. The runner's speed at the end of the 60.0 m is 9.00 m/s. How much time did it take the runner to complete the 60.0 m distance? A) 6.67 s B) 15.0 s C) 9.80 s D) 10.2 s E) 13.3 s Answer: A Var: 1 21) An object starts from rest at time t = 0.00 s and moves in the +x direction with constant acceleration. The object travels 12.0 m from time t = 1.00 s to time t = 2.00 s. What is the acceleration of the object? A) -12.0 m/s2 B) 24.0 m/s2 C) -4.00 m/s2 D) 4.00 m/s2 E) 8.00 m/s2 Answer: E Var: 5 22) A car starts from rest and accelerates with a constant acceleration of 1.00 m/s2 for 3.00 s. The car continues for 5.00 s at constant velocity. How far has the car traveled from its starting point? A) 24.0 m B) 9.00 m C) 19.5 m D) 4.50 m E) 15.0 m Answer: C Var: 1 23) A ball rolls across a floor with an acceleration of 0.100 m/s2 in a direction opposite to its velocity. The ball has a velocity of 4.00 m/s after rolling a distance 6.00 m across the floor. What was the initial speed of the ball? A) 4.15 m/s B) 5.85 m/s C) 4.60 m/s D) 5.21 m/s E) 3.85 m/s Answer: A Var: 1

24) A car is 200 m from a stop sign and traveling toward the sign at 40.0 m/s. At this time, the driver suddenly realizes that she must stop the car. If it takes 0.200 s for the driver to apply the brakes, what must be the magnitude of the constant acceleration of the car after the brakes are applied so that the car will come to rest at the stop sign? A) 2.89 m/s2 B) 3.89 m/s2 C) 4.17 m/s2 D) 3.42 m/s2 E) 2.08 m/s2 Answer: C Var: 1 25) A speeding car is traveling at a constant 30.0 m/s when it passes a stationary police car. If the police car delays for 1.00 s before starting, what must be the magnitude of the constant acceleration of the police car to catch the speeding car after the police car travels a distance of 300 m? A) 6.00 m/s2 B) 3.00 m/s2 C) 7.41 m/s2 D) 1.45 m/s2 E) 3.70 m/s2 Answer: C Var: 1 26) A soccer ball is released from rest at the top of a grassy incline. After 8.6 seconds, the ball travels 87 meters and 1.0 s after this, the ball reaches the bottom of the incline. (a) What was the magnitude of the ball's acceleration, assume it to be constant? (b) How long was the incline? Answer: a) 2.4 m/s2 b) 110 m Var: 50+ 27) A package is dropped from a helicopter moving upward at 15 m/s. If it takes 16.0 s before the package strikes the ground, how high above the ground was the package when it was released if air resistance is negligible? A) 810 m B) 1000 m C) 1200 m D) 1500 m Answer: B Var: 25

28) A ball is projected upward at time t = 0.0 s, from a point on a roof 90 m above the ground. The ball rises, then falls and strikes the ground. The initial velocity of the ball is 36.2 m/s if air resistance is negligible. The time when the ball strikes the ground is closest to A) 9.4 s B) 9.0 s C) 8.7 s D) 9.7 s E) 10 s Answer: A Var: 50+ 29) At the same moment from the top of a building 3.0 × 102 m tall, one rock is dropped and one is thrown downward with an initial velocity of 10 m/s. Both of them experience negligible air resistance. How much EARLIER does the thrown rock strike the ground? A) 0.95 s B) 0.86 s C) 0.67 s D) They land at exactly the same time. Answer: A Var: 21 30) Two identical objects A and B fall from rest from different heights to the ground and feel no appreciable air resistance. If object B takes TWICE as long as object A to reach the ground, what is the ratio of the heights from which A and B fell? A) hA/hB = 1/ B) hA/hB = 1/2 C) hA/hB = 1/4 D) hA/hB = 1/8 Answer: C Var: 1 31) A foul ball is hit straight up into the air with a speed of 30.0 m/s. (a) Calculate the time required for the ball to rise to its maximum height. (b) Calculate the maximum height reached by the ball. (c) Determine the time at which the ball pass a point 25.0 m above the point of contact between the bat and ball. (d) Explain why there are two answers to part (c). Answer: (a) 3.06 s (b) 45.9 m (c) 0.995 s and 5.13 (d) One value is for the ball traveling upward; one value is for the ball traveling downward. Var: 1

32) A rock is dropped from the top of a vertical cliff and takes 3.00 s to reach the ground below the cliff. A second rock is thrown vertically from the cliff, and it takes this rock 2.00 s to reach the ground below the cliff from the time it is released. With what velocity was the second rock thrown, assuming no air resistance? A) 4.76 m/s upward B) 5.51 m/s downward C) 12.3 m/s upward D) 4.76 m/s downward E) 12.3 m/s downward Answer: E Var: 1 33) To determine the height of a flagpole, Abby throws a ball straight up and times it. She sees that the ball goes by the top of the pole after 0.50 s and then reaches the top of the pole again after a total elapsed time of 4.1 s. How high is the pole above the point where the ball was launched? (You can ignore air resistance.) A) 10 m B) 13 m C) 16 m D) 18 m E) 26 m Answer: A Var: 1 34) A test rocket is fired straight up from rest with a net acceleration of 20.0 m/s2. After 4.00 seconds the motor turns off, but the rocket continues to coast upward with no appreciable air resistance. What maximum elevation does the rocket reach? A) 487 m B) 327 m C) 320 m D) 408 m E) 160 m Answer: A Var: 1 35) A toy rocket is launched vertically from ground level (y = 0.00 m), at time t = 0.00 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 72 m and acquired a velocity of 30 m/s. The rocket continues to rise in unpowered flight, reaches maximum height, and falls back to the ground with negligible air resistance. The speed of the rocket upon impact on the ground is closest to A) 48 m/s B) 44 m/s C) 39 m/s D) 54 m/s E) 59 m/s Answer: A Var: 50+ 32 Copyright © 2013 Pearson Education, Inc.

36) A ball is projected upward at time t = 0.00 s, from a point on a roof 70 m above the ground and experiences negligible air resistance. The ball rises, then falls and strikes the ground. The initial velocity of the ball is 28.5 m/s. Consider all quantities as positive in the upward direction. The velocity of the ball when it is 39 m above the ground is closest to A) -38 m/s. B) -30 m/s. C) -23 m/s. D) -15 m/s. E) -45 m/s. Answer: A Var: 50+ 37) On the earth, when an astronaut throws a 0.250-kg stone vertically upward, it returns to his hand a time T later. On planet X he finds that, under the same circumstances, the stone returns to his hand in 2T. In both cases, he throws the stone with the same initial velocity and it feels negligible air resistance. The acceleration due to gravity on planet X (in terms of g) is A) g/4. B) g/2. C) g/ . D) g . E) 2g. Answer: B Var: 1 38) Two identical stones are dropped from rest and feel no air resistance as they fall. Stone A is dropped from height h, and stone B is dropped from height 2h. If stone A takes time t to reach the ground, stone B will take time A) 4t. B) 2t. C) t . D) t/ . E) t/2. Answer: C Var: 1 39) A rock is thrown directly upward from the edge of the roof of a building that is 66.2 meters tall. The rock misses the building on its way down, and is observed to strike the ground 4.00 seconds after being thrown. Neglect any effects of air resistance. With what speed was the rock thrown? Answer: 3.05 m/s Var: 50+

40) A rocket takes off vertically from the launchpad with no initial velocity but a constant upward acceleration of 2.25 m/s2. At 15.4 s after blastoff, the engines fail completely so the only force on the rocket from then on is the pull of gravity. (a) What is the maximum height the rocket will reach above the launchpad? (b) How fast is the rocket moving at the instant before it crashes onto the launchpad? (c) How long after engine failure does it take for the rocket to crash onto the launchpad? Answer: (a) 328 m (b) 80.2 m/s (c) 11.7 s Var: 1 Physics for Scientists and Engineers, 3e (Knight) Chapter 3 Vectors and Coordinate Systems 3.1 Conceptual Questions 1) Which of the following is an accurate statement? A) The magnitude of a vector can be zero even though one of its components is not zero. B) It is possible to add a scalar quantity to a vector. C) Even though two vectors have unequal magnitudes, it is possible that their vector sum is zero. D) Rotating a vector about an axis passing through the tip of the vector does not change the vector. E) The magnitude of a vector is independent of the coordinate system used. Answer: E Var: 1 2) If = 0, then the vectors directions from each other. A) True B) False Answer: B Var: 1

and

3) Under what condition is |

| = A + B?

A) The magnitude of vector

have equal magnitudes and are directed in the opposite

is zero.

B) Vectors

and

are in opposite directions.

C) Vectors

and

are in the same direction.

D) Vectors and are in perpendicular directions. E) The statement is never true. Answer: B Var: 1 4) If A > B, under what condition is | A) The statement is never true.

| = A - B?

B) Vectors

and

are in opposite directions.

C) Vectors

and

D) Vectors and re in perpendicular directions. E) The statement is always true. Answer: C Var: 1

5) For the vectors shown in the figure, express vector

Answer: Var: 1

in terms of vectors

and

6) The magnitude of a vector can never be less than the magnitude of one of its components. A) True B) False Answer: A Var: 1 7) If the magnitude of vector

is less than the magnitude of vector

less than the x component of A) True B) False Answer: B Var: 1

, then the x component of

8) If the eastward component of vector is equal to the westward component of vector and their northward components are equal. Which one of the following statements about these two vectors is correct? A) Vector

is parallel to vector

B) Vectors

and

C) Vector

is perpendicular to vector

point in opposite directions. .

D) The magnitude of vector

is equal to the magnitude of vector

E) The magnitude of vector Answer: D Var: 1

is twice the magnitude of vector

. .

9) If all the components of a vector are equal to 1, then that vector is a unit vector. A) True B) False Answer: B Var: 1

3.2 Problems 1) You walk 55 m to the north, then turn 60° to your right and walk another 45 m. How far are you from where you originally started? A) 87 m B) 50 m C) 94 m D) 46 m Answer: A Var: 31 2) Vectors

and

are shown in the figure. Vector

is 16.0 units, and the magnitude of vector

is given by

. The magnitude of vector

is 7.00 units. What is the magnitude of vector

A) 9.00 B) 9.53 C) 15.5 D) 16.2 E) 17.5 Answer: D Var: 1

3) Vectors

and

are shown in the figure. Vector

is 16.0 units, and the magnitude of vector counterclockwise from the +x-axis?

is given by

. The magnitude of vector

is 7.00 units. What is the angle of vector

, measured

A) 16.9° B) 22.4° C) 73.1° D) 287° E) 292° Answer: D Var: 1 4) A rabbit trying to escape a fox runs north for 8.0 m, darts northwest for 1.0 m, then drops 1.0 m down a hole into its burrow. What is the magnitude of the net displacement of the rabbit? A) 8.8 m B) 8.1 m C) 66 m D) 10 m Answer: A Var: 50+ 5) You walk 53 m to the north, then turn 60° to your right and walk another 45 m. Determine the direction of your displacement vector. Express your answer as an angle relative to east. A) 63° N of E B) 50° N of E C) 57° N of E D) 69° N of E Answer: A Var: 50+

6) Vector

has a magnitude 5.00 and points in a direction 40.0° clockwise from the negative y axis.

What are the x and y components of vector A) Ax = 3.83 and Ay = 3.21 B) Ax = 3.83 and Ay = -3.21 C) Ax = -3.21 and Ay = -3.83 D) Ax = -3.21 and Ay = 3.83 E) Ax = 4.29 and Ay = 2.16 Answer: C Var: 5 7) The components of vector

are

= + 3.90 and

counterclockwise from the +x-axis to vector A) 314° B) 134° C) 224° D) 136° E) 46.0° Answer: A Var: 1

= -4.00. What is the angle measured

8) Vector has a magnitude of 5.5 cm and points along the x-axis. Vector cm and points at +30° above the negative x-axis. (a) Determine the x and y components of Vector

(b) Determine the x and y components of Vector (c) Determine x and y components of the sum of these two vectors. (d) Determine the magnitude and direction of the sum of these two vectors. Answer: (a) = 5.5 cm, =0 (b)

= -6.5 cm,

= 3.8 cm

(c)

= -1.0 cm,

= 3.8 cm

(d) 3.9 cm at 75° above -x-axis Var: 1

has a magnitude of 7.5

9) Vector

has a magnitude of 75.0 cm and points at 30° above the positive x-axis. Vector

magnitude of 25.0 cm and points along the negative x-axis. Vector points at 45° below the negative x-axis. (a) Determine the x and y components of Vector

(b) Determine the x and y components of Vector

has a

has a magnitude of 40.0 cm and

(c) Determine the x and y components of Vector . (d) Determine x and y components of the sum of these three vectors. (e) Determine the magnitude and direction of the sum of these three vectors. Answer: (a) = 65 cm, = 38 cm (b)

= -25 cm,

(c)

= -28 cm,

= -28 cm

(d)

= 12 cm,

= 9.2 cm

(e) 15 cm at 38° above +x-axis Var: 1 10) A helicopter is flying horizontally with a speed of 444 m/s over a hill that slopes upward with a 2% grade (that is, the "rise" is 2% of the "run"). What is the component of the helicopter's velocity perpendicular to the sloping surface of the hill? A) 8.9 m/s B) 220 m/s C) 435 m/s D) 444 m/s Answer: A Var: 50+ 11) An apple falls from an apple tree growing on a 20° slope. The apple hits the ground with an impact velocity of 16.2 m/s straight downward. What is the component of the apple's impact velocity parallel to the surface of the slope? A) 5.5 m/s B) 8.7 m/s C) 12 m/s D) 15 m/s Answer: A Var: 50+

12) The components of vector given are

= -6.1 and

are

= +2.2 and

= -6.9 , and the components of vector

= -2.2. What is the magnitude of the vector

are

A) 9.5 B) 6.1 C) 9.9 D) 91 E) 0.76 Answer: A Var: 50+ 13) The components of vector = -6 and

are

= -3.5 and

= -9.7, and the components of vector

= +8.1. What is the angle (less than 180 degrees) between vectors

and

are ?

A) 124° B) 56° C) 17° D) 163° E) 106° Answer: A Var: 50+ 14) An airplane undergoes the following displacements: First, it flies 66 km in a direction 30° east of north. Next, it flies 49 km due south. Finally, it flies 100 km 30° north of west. Using vector components, determine how far the airplane ends up from its starting point. A) 79 km B) 81 km C) 82 km D) 78 km E) 76 km Answer: A Var: 1

15) In the figure, the magnitude of vector

is 18.0 units, and the magnitude of vector

is 12.0 units.

What vector must be added to the vectors and so that the resultant of these three vectors points in the -x direction and has a magnitude of 7.50 units? Use vector components to find your answer, and express vector by giving its magnitude and the angle it makes with the +x-axis taking counterclockwise to be positive.

Answer: 15.5, 209° Var: 1 16) Three forces are exerted on an object placed on a tilted floor. Forces are vectors. The three forces are directed as shown in the figure. If the forces have magnitudes = 1.0 N, = 8.0 N and = 7.0 N, where N is the standard unit of force, what is the component of the net force parallel to the floor?

net =

17) As shown in the figure, three force vectors act on an object. The magnitudes of the forces as shown in the figure are = 80.0 N, = 60.0 N, and = 40.0 N, where N is the standard SI unit of force. The resultant force acting on the object is given by

A) 180 N at an angle 60.0° with respect to +x-axis. B) 60.0 N at an angle 90.0° with respect to +x-axis. C) 20.0 N at an angle 34.3° with respect to +x-axis. D) 35.5 N at an angle 34.3° with respect to +x-axis. E) 40.0 N at an angle 60.0° with respect to +x-axis. Answer: D Var: 1 18) A teacher sends her students on a treasure hunt. She gives the following instructions: 1. Walk 300 m north 2. Walk 400 m northwest 3. Walk 700 m east-southeast and the treasure is buried there. As all the other students walk off following the instructions, Jane physics student quickly adds the displacements and walks in a straight line to find the treasure. How far and in what direction does Jane need to walk? A) 187 m in a direction 67.3° north of east B) 481 m in a direction 40.9° north of east C) 399 m in a direction 52.5° north of east D) 284 m in a direction 28.2° west of north E) The treasure position cannot be reached in one straight walk. Answer: B Var: 1

19) Vector

= -3.00 + 3.00 and vector

= 3.00 + 4.00 . What is vector

A) 0.00 + 3.00 B) 7.00 + 7.00 C) -3.00 + 7.00 D) 0.00 + 7.00 E) -3.00 -3.00 Answer: D Var: 1 20) Vector

= 1.00 + -2.00 and vector

= 3.00 + 4.00 . What are the magnitude and direction of

vector = + ? A) 7.21 in a direction 33.7° counterclockwise from the positive x axis B) 6.00 in a direction 63.4° counterclockwise from the positive x axis C) 4.47 in a direction 6.34° counterclockwise from the positive x axis D) 4.47 in a direction 26.6° counterclockwise from the positive x axis E) 7.21 in a direction 56.3° counterclockwise from the positive x axis Answer: D Var: 1 21) What is the magnitude of

, where

= -4

-2 - 3

= 1.00 + 4.00 - 1.00 ,

= 3.00 - 1.00 - 4.00

and = -1.00 + 1.00 ? A) 7.07 B) 2.00 C) 10.76 D) 6.78 E) 8.12 Answer: A Var: 9 22) If

= +4 - 2 - 3

magnitude of A) 8 B) 7 C) 9 D) 10 E) 11 Answer: A Var: 50+

and

, which of the following numbers is closest to the

23) Vector

= -1.00 + -2.00 and vector

= 3.00 + 4.00 . What are the magnitude and direction of

vector = 3.00 + 2.00 ? A) 3.61 in a direction -56.3° counterclockwise from the positive x-axis B) 3.61 in a direction 56.3° counterclockwise from the positive x-axis C) 3.61 in a direction 33.7° counterclockwise from the positive x-axis D) 5.00 in a direction 56.3° counterclockwise from the positive x axis E) 6.72 in a direction 34.4° counterclockwise from the positive x-axis Answer: C Var: 1 24) Vectors

and

are shown in the figure. What is

A) 31.8 B) -32.0 - 2.00 C) 1028 D) 34.0 E) -2.00 - 32.0 Answer: A Var: 1 Physics for Scientists and Engineers, 3e (Knight) Chapter 4 Kinematics in Two Dimensions 4.1 Conceptual Questions 1) Shown below are the velocity and acceleration vectors for a person in several different types of motion. In which case is the person slowing down and turning to his right? A)

Answer: B Var: 1

2) While an object is in projectile motion (with upward being positive) with no air resistance A) the horizontal component of its velocity remains constant and the horizontal component of its acceleration is equal to -g. B) the horizontal component of its velocity remains constant and the vertical component of its acceleration is equal to -g. C) the horizontal component of its velocity remains constant and the vertical component of its acceleration is equal to zero. D) the vertical component of both its velocity and its acceleration remain constant. E) the vertical component of its velocity remains constant and the vertical component of its acceleration is equal to -g. Answer: B Var: 1 3) For general projectile motion, when the projectile is at the highest point of its trajectory A) its acceleration is zero. B) its velocity is perpendicular to the acceleration. C) its velocity and acceleration are both zero. D) the horizontal component of its velocity is zero. E) the horizontal and vertical components of its velocity are zero. Answer: B Var: 1 4) Alice and Tom dive from an overhang into the lake below. Tom simply drops straight down from the edge, but Alice takes a running start and jumps with an initial horizontal velocity of 25 m/s. Neither person experiences any significant air resistance. Just as they reach the lake below A) the speed of Alice is larger than that of Tom. B) the splashdown speed of Alice is larger than that of Tom. C) they will both have the same speed. D) the speed of Tom will always be 9.8 m/s larger than that of Alice. E) the speed of Alice will always be 25 m/s larger than that of Tom. Answer: A Var: 1 5) Alice and Tom dive from an overhang into the lake below. Tom simply drops straight down from the edge, but Alice takes a running start and jumps with an initial horizontal velocity of 25 m/s. Neither person experiences any significant air resistance. Compare the time it takes each of them to reach the lake below. A) Alice reaches the surface of the lake first. B) Tom reaches the surface of the lake first. C) Alice and Tom will reach the surface of the lake at the same time. Answer: C Var: 1

6) Jan and Len throw identical rocks off a tall building at the same time. The ground near the building is flat. Jan throws her rock straight downward. Len throws his rock downward and outward such that the angle between the initial velocity of the rock and the horizon is 30°. Len throws the rock with a speed twice that of Jan's rock. If air resistance is negligible, which rock hits the ground first? A) They hit at the same time. B) Jan's rock hits first. C) Len's rock hits first. D) It is impossible to know from the information given. Answer: A Var: 1 7) A monkey is sitting at the top of a tree 20 m above ground level. A person standing on the ground wants to feed the monkey. He uses a bow and arrow to launch the food to the monkey. If the person knows that the monkey is going to drop from the tree at the same instant that the person launches the food, how should the person aim the arrow containing the food? Air resistance is small enough to be ignored. A) He should aim it at the monkey. B) He should aim it below the monkey. C) He should aim it above the monkey. Answer: A Var: 1 8) A pilot drops a package from a plane flying horizontally at a constant speed. Neglecting air resistance, when the package hits the ground the horizontal location of the plane will A) be behind the package. B) be over the package. C) be in front of the package. D) depend of the speed of the plane when the package was released. Answer: B Var: 1 9) For an object in uniform circular motion, its velocity and acceleration vectors are always perpendicular to each other at every point in the path. A) True B) False Answer: A Var: 1 10) If an object travels at a constant speed in a circular path, the acceleration of the object is A) larger in magnitude the smaller the radius of the circle. B) in the same direction as the velocity of the object. C) smaller in magnitude the smaller the radius of the circle. D) in the opposite direction of the velocity of the object. E) zero. Answer: A Var: 1

11) Point P in the figure indicates the position of an object traveling at constant speed clockwise around the circle. Which arrow best represents the direction of the acceleration of the object at point P?

C) D)

Answer: D Var: 1 12) If you set the cruise control of your car to a certain speed and take a turn, the speed of the car will remain the same. Is the car accelerating? A) Yes B) No Answer: A Var: 1

4.2 Problems 1) Object A has a position as a function of time given by A(t) = (3.00 m/s)t + (1.00 m/s2)t2 . Object B has a position as a function of time given by B(t) = (4.00 m/s)t + (-1.00 m/s2)t2 . All quantities are SI units. What is the distance between object A and object B at time A) 34.6 m B) 15.0 m C) 18.3 m D) 3.46 m E) 29.8 m Answer: C Var: 5 2) An object has a position given by = [2.0 m + (5.00 m/s)t] + [3.0 m - (2.00 m/s2)t2] , where quantities are in SI units. What is the speed of the object at time t = 2.00 s? A) 6.40 m/s B) 9.43 m/s C) 7.00 m/s D) 7.65 m/s E) 13.0 m/s Answer: B Var: 5 3) An object has a position given by = [2.0 m + (3.00 m/s)t] + [3.0 m - (2.00 m/s2)t2] , where all quantities are in SI units. What is the magnitude of the acceleration of the object at time t = 2.00 s? A) 1.00 m/s2 B) 0.00 m/s2 C) 0.522 m/s2 D) 4.00 m/s2 E) 2.00 m/s2 Answer: D Var: 5 4) The horizontal coordinates of a FrisbeeTM in a strong wind are given by where x and y are in meters, and t is in seconds. (a) What is the acceleration of the Frisbee? Give a magnitude and a direction, measuring angles from the positive x direction. (b) What is the magnitude of the velocity at t = 2.0 s, accurate to the nearest m/s? Answer: (a) 10 m/s2, 323° (b) 4 m/s Var: 1

5) An electron moves with a constant horizontal velocity of 3.0 x 106 m/s and no initial vertical velocity as it enters a deflector inside a TV tube. The electron strikes the screen after traveling 17.0 cm horizontally and 40.0 cm vertically upward with no horizontal acceleration. What is the constant vertical acceleration provided by the deflector? (The effects of gravity can be ignored.) A) 2.5 × 1014 m/s2 B) 8.3 × 102 m/s2 C) 1.4 × 104 m/s2 D) 1.2 × 1014 m/s2 Answer: A Var: 50+ 6) A hockey puck slides off the edge of a table at point A with an initial velocity of 20.0 m/s and experiences no air resistance. The height of the tabletop above the ground is 2.00 m. (a) What is the speed (not the velocity) of the puck just before it touches the ground? (b) What is the distance between point A and the point where the puck hits the ground? Answer: (a) 21.0 m/s (b) 12.9 m Var: 1 7) A hockey puck slides off the edge of a table with an initial velocity of 28.0 m/s. and experiences no air resistance. The height of the tabletop above the ground is 2.00 m. What is the angle below the horizontal of the velocity of the puck just before it hits the ground? A) 77.2° B) 72.6° C) 12.8° D) 12.6° E) 31.8° Answer: D Var: 6 8) A boy throws a rock with an initial velocity of 2.15 m/s at 30.0° above the horizontal. If air resistance is negligible, how long does it take for the rock to reach the maximum height of its trajectory? A) 0.110 s B) 0.194 s C) 0.215 s D) 0.303 s Answer: A Var: 50+ 9) What is the maximum distance we can shoot a dart, from ground level, provided our toy dart gun gives a maximum initial velocity of 2.78 m/s and air resistance is negligible? A) 0.789 m B) 1.58 m C) 1.39 m D) 0.394 m Answer: A Var: 50+

10) A catapult is tested by Roman legionnaires. They tabulate the results in a papyrus and 2000 years later the archaeological team reads (distances translated into modern units): Range = 0.20 km; angle of launch = π/4; landing height = launch height. What is the initial velocity of launch of the boulders if air resistance is negligible? A) 44 m/s B) 1.4 m/s C) 22 m/s D) 0.69 m/s Answer: A Var: 20 11) A hobby rocket reaches a height of 72.3 m and lands 111 m from the launch point with no air resistance. What was the angle of launch? A) 69.0° B) 67.4° C) 22.6° D) 44.8° Answer: A Var: 50+ 12) A ball is thrown at a 60.0° angle above the horizontal across level ground. It is thrown from a height of 2.00 m above the ground with a speed of 20.0 m/s and experiences no appreciable air resistance. The time the ball remains in the air before striking the ground is closest to A) 16.2 s. B) 3.07 s. C) 3.32 s. D) 3.53 s. E) 3.64 s. Answer: E Var: 5 13) A rock is thrown at a window that is located 18.0 m above the ground. The rock is thrown at an angle of 40.0° above horizontal. The rock is thrown from a height of 2.00 m above the ground with a speed of 30.0 m/s and experiences no appreciable air resistance. If the rock strikes the window on its upward trajectory, from what horizontal distance from the window was it released? A) 53.2 m B) 48.7 m C) 71.6 m D) 29.8 m E) 27.3 m Answer: E Var: 1

14) An airplane is flying at a speed of 2.00 102 m/s in level flight at an altitude of 8.00 102 m. A package is to be dropped from the airplane to land on a target on the ground. Ignore air resistance. (a) At what horizontal distance away from the target should the package be released so that it lands on the target? (b) In what direction relative to the horizontal will the package be traveling when it hits the ground? Answer: (a) 2.56 km (b) 32.1° below the horizontal Var: 1 15) A child throws a ball with an initial speed of 8.00 m/s at an angle of 40.0° above the horizontal. The ball leaves her hand 1.00 m above the ground and experience negligible air resistance. (a) How far from where the child is standing does the ball hit the ground? (b) How long is the ball in flight before it hits the ground? Answer: (a) 7.46 m (b) 1.22 s Var: 1 16) A child throws a ball with an initial speed of 8.00 m/s at an angle of 40.0° above the horizontal. The ball leaves her hand 1.00 m above the ground and experience negligible air resistance. (a) What is the magnitude of the ball's velocity just before it hits the ground? (b) At what angle below the horizontal does the ball approach the ground? Answer: (a) 9.14 m/s (b) 47.9° Var: 1 17) A projectile is fired from point 0 at the edge of a cliff, with initial velocity components of and , as shown in the figure.The projectile rises and then falls into the sea at point P. The time of flight of the projectile is 40.0 s, and it experiences no appreciable air resistance in flight. What is the magnitude of the velocity of the projectile 21.0 s after it is fired?

Answer: 67.4 m/s Var: 1

18) A projectile is fired from point 0 at the edge of a cliff, with initial velocity components of v0x = 60.0 m/s and v0y = 175 m/s, as shown in the figure. The projectile rises and then falls into the sea at point P. The time of flight of the projectile is 40.0 s, and it experiences no appreciable air resistance in flight. What is the height of the cliff?

Answer: 840 m Var: 1 19) A hiker throws a stone from the upper edge of a vertical cliff. The stone's initial velocity is 25.0 m/s directed at 40.0° with the face of the cliff, as shown in the figure. The stone hits the ground 3.75 s after being thrown and feels no appreciable air resistance as it falls. (a) What is the height of the cliff? (b) How far from the foot of the cliff does the stone land? (c) How fast is the stone moving just before it hits the ground?

Answer: (a) 141 m Var: 1

(b) 60.3 m

20) A projectile returns to its original height 4.08 s after being launched, during which time it travels 76.2 m horizontally. If air resistance can be neglected, what was the projectile's initial speed? Answer: 27.4 m/s Var: 1 21) A plane flying at 70.0 m/s suddenly stalls. If the acceleration during the stall is 9.8 m/s2 directly downward, the stall lasts 5.0 s, and the plane was originally climbing at 25° to the horizontal, what is the velocity after the stall? A) 66 m/s at 17° below the horizontal B) 66 m/s at 17° above the horizontal C) 80 m/s at 37° below the horizontal D) 80 m/s at 37° above the horizontal Answer: A Var: 1 22) A rescue plane flying horizontally at 72.6 m/s spots a survivor in the ocean 182 m directly below and releases an emergency kit with a parachute. . Because of the shape of the parachute, it experiences insignificant horizontal air resistance. If the kit descends with a constant vertical acceleration of how far away from the survivor will it hit the waves? A) 574 m B) 4.54 km C) 406 m D) 602 m Answer: A Var: 50+ 23) An airplane flies between two points on the ground that are 500 km apart. The destination is directly north of the origination of the flight. The plane flies with an air speed of 120 m/s. If a constant wind blows at 10.0 m/s due west during the flight, what direction must the plane fly relative to north to arrive at the destination? A) 4.78° east of north B) 4.76° east of north C) 85.2° west of north D) 4.78° west of north E) 4.76° west of north Answer: A Var: 1 24) A plane has an eastward heading at a speed of 156 m/s (relative to the air). A 20.0 m/s wind is blowing southward while the plane is flying. The velocity of the plane relative to the ground is A) 157 m/s at an angle 7.31° south of east. B) 157 m/s at an angle 7.31° east of south. C) 155 m/s at an angle 7.36° south of east. D) 155 m/s at an angle 7.36° east of south. E) 157 m/s at an angle 7.36° south of east. Answer: A Var: 1 55 Copyright © 2013 Pearson Education, Inc.

25) A swimmer heading directly across a river 200 m wide reaches the opposite bank in 6 min 40 s, during which time she is swept downstream 480 m. (a) How fast can she swim in still water? (b) What is the speed of the current? Answer: (a) 0.50 m/s (b) 1.2 m/s Var: 1 26) A small boat is moving at a velocity of 3.35 m/s when it is accelerated by a river current perpendicular to the initial direction of motion. If the acceleration of the current is 0.750 m/s2, what will be the new velocity of the boat after 33.5 s? A) 25.3 m/s at 82.4° from initial direction of motion B) 25.3 m/s at 7.59° from initial direction of motion C) 640.1 m/s at 82.4° from initial direction of motion D) 640.1 m/s at 7.59° from initial direction of motion Answer: A Var: 50+ 27) You want to swim straight across a river that is 76 m wide. You find that you can do this if you swim at an angle of θ = 28° from the upstream direction at a constant rate of 1.5 m/s relative to the water. At what rate does the river flow? The angle θ is measured from the river bank (directly upstream is θ = 0° while directly across the river is θ = 90°). A) 1.3 m/s B) 0.70 m/s C) 1.6 m/s D) 1.8 m/s Answer: A Var: 14 28) A long-distance swimmer is able to swim through still water at 4.0 km/h. She wishes to try to swim from Port Angeles, Washington, directly north to Victoria, British Columbia, a distance of 50 km. An ocean current flows through the Strait of Juan de Fuca from west to east at 3.0 km/h. In what direction (relative to north) should she swim to make the crossing along a straight line between the two cities? A) 37° west of north B) 37° east of north C) 41° west of north D) 41° east of north E) 49° west of north Answer: E Var: 1

29) A plane flies directly between two cities, A and B, which are separated by 2300 mi. From A to B, the plane flies into a 65 mi/h headwind. On the return trip from B to A, the wind velocity is unchanged. The trip from B to A takes 65 min less than the trip from A to B. What is the airspeed of the plane, assuming it is the same in both directions? A) 530 mi/h B) 400 mi/h C) 480 mi/h D) 610 mi/h Answer: A Var: 31 30) A cart is moving with a constant horizontal velocity of 5.00 m/s. A small pebble is launched from the front of the cart with a velocity of 8.00 m/s at 60.0° above the horizontal as measured relative to the cart (see figure) and experiences no significant air resistance. Just as the pebble returns to the level from which it was launched, its distance from the front of the cart is closest to

A) 2.83 m. B) 4.60 m. C) 5.66 m. D) 9.19 m. E) 11.3 m. Answer: C Var: 1 31) A ball is tied to the end of a cable of negligible mass. The ball is spun in a circle with a radius 2.00 m making 7.00 revolutions every 10.0 seconds. What is the magnitude of the acceleration of the ball? A) 67.9 m/s2 B) 38.7 m/s2 C) 29.3 m/s2 D) 14.8 m/s2 E) 74.2 m/s2 Answer: B Var: 1

32) An electrical motor spins at a constant 2857.0 rev/min. If the armature radius is 2.685 cm, what is the acceleration of the outer edge of the armature? A) 2403 m/s2 B) 844.4 m/s2 C) 241,100 m/s2 D) 84.40 m/s2 Answer: A Var: 50+ 33) A satellite orbits the earth a distance of 1.50 × 107 m above the planet's surface and takes 8.65 hours for each revolution about the earth. The earth's radius is 6.38 × 106 m. The acceleration of this satellite is closest to A) 0.0690 m/s2. B) 0.870 m/s2. C) 1.91 m/s2. D) 2.72 m/s2. E) 9.80 m/s2. Answer: B Var: 1 34) An aircraft performs a maneuver called an "aileron roll." During this maneuver, the plane turns like a screw as it maintains a straight flight path, which sets the wings in circular motion. If it takes it 35 s to complete the circle and the wingspan of the plane is 11 m, what is the acceleration of the wing tip? A) 0.18 m/s2 B) 0.99 m/s2 C) 5.6 m/s2 D) 1.0 m/s2 Answer: A Var: 50+ 35) An object moves in a circle of radius R at constant speed with a period T. If you want to change only the period in order to cut the object's acceleration in half, the new period should be A) T/4. B) T/2. C) T/

D) T . E) 4T. Answer: D Var: 1

36) A wind farm generator uses a two-bladed propeller (see figure) mounted on a pylon at a height of 20 m. The length of each propeller blade is 12 m. A small piece from the tip of the propeller breaks off when the propeller is vertical. At that instant, the period of the motion of the propeller is 1.2 s. The fragment flies off horizontally, falls with negligible air resistance, and strikes the ground at P. (a) How far is point P from the base of the pylon? (b) At what angle with respect to the vertical is the fragment moving just as it strikes the ground at P?

Answer: (a) 160 m Var: 1

(b) 68°

37) A disk-shaped space station 175 m in diameter spins uniformly about an axis perpendicular to the plane of the disk through its center. How many rpm (rev/min) must this disk make so that the acceleration of all points on its rim is g/2? Answer: 2.26 rev/min Var: 1 38) Two particles, A and B, are in uniform circular motion about a common center. The acceleration of particle A is 8.5 times that of particle B. The period of particle B is 2.0 times the period of particle A. The ratio of the radius of the motion of particle A to that of particle B is closest to A) rA/rB = 2.1. B) rA/rB = 4.3. C) rA/rB = 18. D) rA/rB = 0.24. E) rA/rB = 17. Answer: A Var: 50+ Physics for Scientists and Engineers, 3e (Knight) Chapter 5 Force and Motion 5.1 Conceptual Questions 1) Point P in the figure indicates the position of an object traveling at constant speed clockwise around the circle. Which arrow best represent the direction the object would travel if the net external force on it were suddenly reduced to zero?

C) D)

Answer: D Var: 1

2) An object is moving to the right, and experiencing a net force that is directed to the right. The magnitude of the force is decreasing with time. The speed of the object is A) increasing. B) decreasing. C) constant in time. Answer: A Var: 1 3) A stalled car is being pushed up a hill at constant velocity by three people. The net force on the car is A) zero. B) up the hill and equal to the weight of the car. C) down the hill and equal to the weight of the car. D) up the hill and greater than the weight of the car. E) down the hill and greater than the weight of the car. Answer: A Var: 1 4) A 615 N student standing on a scale in an elevator notices that the scale reads 645 N. From this information, the student knows that the elevator must be moving A) downward. B) upward. C) You cannot tell if it is moving upward or downward. Answer: C Var: 1 5) A car is being towed at constant velocity on a horizontal road using a horizontal chain. The tension in the chain must be equal to the weight of the car in order to maintain constant velocity. A) True B) False Answer: B Var: 1 6) You are standing in a moving bus, facing forward, and you suddenly fall forward as the bus comes to an immediate stop. The force acting on you that causes you to fall forward is A) the force of gravity. B) the normal force due to your contact with the floor of the bus. C) the force due to static friction between you and the floor of the bus. D) the force due to kinetic friction between you and the floor of the bus. E) No forces were acting on you to cause you to fall. Answer: E Var: 1

7) Which one of the following free-body diagrams best represents the free-body diagram, with correct relative force magnitudes, of a person in an elevator that is traveling upward with an unchanging velocity? A)

f is the force of the floor on the person and

g is the force of gravity on the person.

Answer: B Var: 1