PPYQ

The position vector of a particle R as a function of time t is given by → R = 4 sin [ 2 πt ] ˆ i + 4 cos [ 2 πt ] ˆ j R→=4sin2πti^+4cos2πtj^ Where R is in meters, t is in seconds and ˆ i , ˆ j i^, j^ denote unit vectors along x and y-directions, respectively. Which one of the following statements is wrong for the motion of the particle? 1. Acceleration is along − → R -R→. 2. Magnitude of the acceleration vector is v 2 R v2R, where v is the velocity of the particle. 3. Magnitude of the velocity of the particle is 8 m/s. 4. Path of the particle is a circle of radius 4m.

Ruhul Amin Alig

PPYQ

A particle of mass 10 g moves along a circle of radius 6.4 cm with a constant tangential acceleration. What is the magnitude of this acceleration, if the kinetic energy of the particle becomes equal to 8 x 10-4 J by the end of the second revolution after the beginning of the motion? 1. 0.15 m/s2 2. 0.18 m/s2 3. 0.2 m/s2 4. 0.1 m/s2

Ruhul Amin Alig

PPYQ

The position of a particle with respect to time t along the x-axis is given by 9t2 – t3 where x is in metre and t in second. What will be the position of this particle when it achieves maximum speed along the +x direction? 1. 32 m 2. 54 m 3. 81 m 4. 24 m

Ruhul Amin Alig

PPYQ

A man throws some balls with the same speed vertically upwards one after the other at an interval of 2 seconds. What should be the speed of the throw so that more than two balls are in the sky at any time? (Given g = 9.8 m/s2) 1. More than 19.6 m/s 2. At least 9.8 m/s 3. Any speed less than 19.6 m/s 4. Only with speed 19.6 m/s

Ruhul Amin Alig

PPYQ

If a ball is thrown vertically upwards with speed u, the distance covered during the last ‘t’ seconds of its ascent is: 1. ut 2. 1 2 gt 2 12gt2 3. ut − 1 2 gt 2 ut-12gt2 4. ( u + gt ) t (u+gt)t

Ruhul Amin Alig