Introductory Physics I - PHYS 200 LAB 2 COMPLETE SOLUTION 2026 ATHABASCA UNIVERSITY

Procedure: Motion with Uniform Velocity: In this experiment I used an extra small tennis ball, a measuring tape measuring a distance of 70cm, and my phone to record the video. On the floor, I placed my measuring tape down and gently rolled the ball directly beside the tape for the full length of 70cm while recording the action perpendicularly against where the ball was travelling.

Motion with Uniform Acceleration: In this experiment I used an extra small tennis ball, a measuring tape that measured the distance of 2m from the ground up the wall, and my phone to record the video. Holding the ball close to, but not against the wall at the height of 2m, I then dropped the ball and let it fall to the ground.

Pictures:

Data:

Analysis and Discussion:

In this lab, the experiment was divided into two parts, motion with uniform velocity and motion with uniform acceleration. To investigate the kinematics of a moving ball, the app Tracker was used to perform a frame-by-frame analysis.

Motion with Uniform Velocity: Once the video was uploaded, the initial time was adjusted to set 0 seconds when the ball was about to start moving. The length was calibrated to match the measuring tape length (known distance) in the video which was 70cm. Next, the x-axis was aligned with the balls path of travel.

To begin tracking the ball, a new point mass track was created, and data points were collected by clicking at the center of the ball at each frame on the x-axis, giving all the x and y coordinates. After finding all the data points, a position (x) vs. time (t) graph was made where t was on the horizontal axis and x on the vertical. Used the curve fitter tool to place a line of best fit and equation x=At+B where A is the slope, and B is the intercept.

Motion with Uniform Acceleration: The video of the ball in free fall was uploaded and the initial time was adjusted for 0 seconds

to be set just before the ball was dropped. The length was calibrated to match the measuring tape length (known distance) in the video which was 2m. Next, the y-axis was aligned with the balls path of travel. To begin tracking the ball, a new point mass track was created, and data points were collected by clicking at the center of the ball at each frame on the y-axis, giving all the coordinates. Next a position (y) vs. time (t) graph was plotted where y is on the vertical axis and t on the horizontal. Using the curve fitter tool, the parabolic model y=At^2+Bt+C was fit to the data points.

Errors: • Calibration errors (time adjustment, measurement unit accuracy) • Human error plotting the data points at the center of the ball • Frame rate is limited Conclusion: In this experiment, we analyzed the kinematics of a ball moving with uniform velocity and uniform acceleration using Tracker

software. For uniform velocity, the position vs. time data fit a linear model, confirming the ball moved at a constant speed. For uniform acceleration, the position vs. time data fit a parabolic model, supporting the assumption of constant gravitational acceleration. The fit parameters were consistent with theoretical values, and the uncertainties were within acceptable limits.

Sources of error were primarily due to calibration and measurement techniques, suggesting improvements in video quality and measurement precision for future experiments.

Questions: 1. From your best-fit linear graph corresponding to uniform motion, estimate the speed of the rolling ball in km/h.

0.4m/s x 3.6 = 1.44km/h 2. Based on your best-fit analysis of the free-falling ball, estimate the acceleration (𝑔) due to gravity. How does your experimental estimation of 𝑔 compare to the known value?