3. A porticle moves in a circle of radius R. In half the period of revolution its displacement is and distance covered is

i do  not know your answer

Explanation:

be subject to a force andchange its motion

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.