One stone is projected horizontally from a `20 m` high cliff with an initial speed of `10 ms^(-1)`. A second stone is simultaneously dropped from that cliff. Which of the following is true?

Options

A. Both strike the ground with same speed.
B. Tha ball with initial speed `10ms^(-1)` reaches the ground first.
C. The ball which is dropped, reaches the ground first.
D. Both strike the ground with different speed

Answer

D

Explanation

10 m/s `=u_(A), u_(B)=0m//s u_(A)=10 hati`

On reaching the ground
Both will have same vertical velocity
`V_(y)^(2)=u^(2)+2a_(y)s_(y)`
since `u_(y)=0` for both A and B
`a_(y)=g` for both A and B
`s_(y)=20 m` for both A and B
Thats why the time taken by both are same