fi BANSAL CLASSES Target IIT JEE 2007
PHYSICS
Daily Practice Problems
CLASS: XI (P, Q, R, S) DATE: 20-21/06/2005 MAX.TIME: 60Min. DPP. NO.-22 Q. 1 System is shown infigure.All the surfaces are smooth. Rod is moved by external agent 2 with acceleration 9 m/s vertically downwards. Force exerted on the rod by the wedge will be: (A) 120 N (B) 200 N (C) 135/2 N (D) 225/2 N Q.2
In thefigureshown ihe block B moves down wife a velocity 10 m/s. The velocity ofA in the position shown is: (A) 12.5 m/s (B) 25 m/s (C) 6.25 m/s (D) none of these
Q. 3
A sphere of mass m is kept between two inclined walls, as shown in thefigure.If the coefficient offrictionbetween each wall aid the sphere is zero, then the ratio of normal reaction (N,/N2) offered by the walls 1 and 2 on the sphere will be (A) tone (B)tan29 (G) 2cos9 (D)cos20
Q.4
How coulda 10kg object be lowered downfroma height using a cord with a breaki^j strength of 80 N, without breaking the cord. (A) lowering the object very slowly (B) lowering it with an acceleration less than 2 m/s2. (C) lowering it with an acceleration greater than 2 m/s2. (D) object cannot be lowered down without breaking the cord.
Q.5
A block of weight 9.8N is placed on a table. The table surface exerts an upward force of 10N on the block. Assume g=9.8m/s2. (A) The block exerts a force of 1 ON on the table (B) The block exertsaforce of 19.8N on 1he table (C) The block exerts a force of 9.8N on the table (D) The block has an upward acceleration. Ifthe strings in inextensible, determine the velocity u of each block in terms of v and 0. (i)Fig.(A) u = (ii) Fig. (B) . u ^ ut[
Q. 6
Q.7
Trajectories are shown in figure for three kicked footballs. Ignoring air resistance, order the trajectories according to (a) time of flight (b) initial vertical velocity component (c) initial horizontal velocity component (d) initial speed. Order from largest to smallest.
Q.8
Find the tension T needed to hold the cart in equilibrium, ifthere is no
Q.9
Ablock of mass 10 kg is kept on ground. A vertically upward force F = 20t N, where t is the time in seconds starts acting on it at t = 0. Find the time at which the normal reaction acting on the block is zero. The height of the block from ground at t = 10 sec.
(a) (b)
friction.
T
Q. 10 A steel ball is suspendedfromthe ceiling of an accelerating carriage by means of two cords A and B. Determine the acceleration a ofthe carriage which will cause the tension in A to be twice that in B. —Q
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