From the top of a tower of height 200 m, a ball A is projected up with speed `10ms^(-1)` and 2 s later, another ball B is projected vertically down with the same speed. Then

Options

A. Both A and B will reach the ground simultaneously
B. Ball A with hit the ground 2 s later than B hitting the ground
C. Both the balls will hit the ground with the same velocity
D. Both will rebound to the same height from the ground, if both have same coefficient of restitution.

Answer

A, C, D

Explanation

a,c,d. Total displacement ball A in 2s,
`S = ut - 1/2"gt"^2 = 10 xx 2 - 1/2 xx 10 xx (2)^2 = 0`
Hence, both A and B will reach the ground simultaneously and
strike with the same velocity.