Question

A man standing on the edge of the terrace of a high rise building throws a stone vertically up with a speed of 20 m/s. Two seconds later an identical stone is thrown vertically downwards with the same speed of 20 m/s. Then:





(A)


the relative velocity between the two stones remain constant till one hits the ground




(B)


both will have the same kinetic energy when they hit the ground




(C)


the time interval between their hitting the ground is 2 seconds




(D)


if the collisions on the ground are perfectly elastic both will rise to the same height above the ground.




Hint:
Ans (A) (B) (C) (D)

there acn be more than one option correct

Answer 1

A the relative velocity between the two stones remain constant