Question

A body A is thrown vertically upwards with such a velocity that it reaches a maximum height of h. Simultaneously, another body B is dropped from height h. It strikes the ground and does not rebound. The velocity of A relative to B versus time graph is best represented by (upward direction is positive).

Answer 1

Answer:

For the first half, when ball A goes up

V

A

​

=U

A

​

−gT

V

B

​

=−gT

V

AB

​

=V

A

​

−V

B

​

V

AB

​

=U.(1)

For the second half, when ball A comes down

V

A

​

=−gT

V

B

​

=0

V

AB

​

=V

A

​

−V

B

​

V

AB

​

=−gT.(2)

Hence from the equation (1) we observe that relative velocity is independent of T. Which will be valid till ball A reaches maximum height point. It is given time taken in reaching h is t.

Hence for the time t, V

AB

​

will be constant, whereas after time t, relative velocity changes its direction and increases afterwards.Explanation: