 
PHYSICS Class:11 P.S. #3  
 
Q.1 The figure Shows the acceleration of a particle versus time graph. The particle starts from rest at t = 0. Find the approximate velocity at t = 1s. [3]
(A) 0.9 m/s (B) 1.6 m/s (C) 3.6 m/s (D) 0.1 m/s
Q.2 If velocity of the particle is given by , where x denotes the position of the particle and initially particle was at x = 4, then which of the following are correct : [3] (A) at t = 4 sec, the position of the particle is at x = 9 (B) particle acceleration at t = 4 sec, is 1 m/s^{2} (C) particle acceleration is 1/2 m/s^{2} throughout the motion (D) particle will never go in negative direction from its starting position
Q.3 The coordinate of an object is given as a function of time by x = 7t  3t^{2}, where x is in meters and t is in seconds. Its average velocity over the interval from t = 0 to t = 4 s is: [3] (A) 5m/s (B) 5m/s (C) 11m/s (D) 11m/s Q.4 The position of an object in xyplane is given by m. Find the time at which the speed of the particle is m/s. [3] (A) sec. (B) sec. (C) sec. (D) sec. Q.5 The displacment of the particle varies with time according to the relation . Then the velocity of the particle is [3] (A) k e^{bt} (B) (C) kbe^{bt} (D)
Q.6 A street car start to move rectilinearly from station A to the next stop B with an acceleration varying according to the law f = a  bx where a and b are positive constant and x is its distance from station A. The distance AB is then equal to [3] (A) 2a/b (B) a/b (C) a/2b (D) 2a 
Q.7_{ }An elevator cabin has a mass of 900 kg (excluding man's mass) A man is standing in it. When the cabin is pulled upwards with a force of 7000 N, the man feels a normal force of 700 N on his feet. How much normal force (in N) will he feel if we pull the cabin upward with a force of 10,000 N. [5]

 
ANSWERKEY  
 
1 A 2 D 3 B 4 A 5 A 6 A 7 1000  