Physics - Center of Mass Question with Solution | TestHub
A small ball of mass 1 kg is kept in circular path of radius 1m in fixed concentric smooth horizontal ring of radius R. Angular speed of the ball in the circular motion is 1 rad/s. At a certain moment the string, which kept the ball in the circular path breaks and the ball goes off tangentially to the wall of rigid, fixed ring and bounces off elastically and again hits the ring and bounces off. After completing one round about the centre, the seventh collision takes place exactly at the position of the first collision.
Following quantities of the ball will remain a constant relative to the centre of the ring during one complete cycle of collisions.
Options:
Answer:
Solution:
Every collision with the ring is elastic, so the speed - and hence the kinetic energy - of the ball stays constant. Momentum, velocity and acceleration all change with direction at each bounce. Answer: (B)
