A stone, dropped from a certain height can reach the ground in 10 s. If it is stopped after 5 s of its fall and then allowed to fall again, find the time taken by it to reach the ground for the remaining distance.

Options

A. 5 sec
B. 10 sec
C. 8.67 sec
D. 10 s

Answer

c

Explanation

Let h be the height from which stone is dropped
`h=(1)/(2)xxgxx(10)^(2)=50 g`
Distance covered in first fall of 5 s.
`h=(1)/(2)xxgxx(5)^(2)=(25)/(2)g`
`t^(2)=75` or `t=sqrt(75)=8.66s`