A body falls on the ground from a height of 10 metre and rebounds to a height of 2.5 m. The ratio of the velocity of the body before collision to the velocity of the body after collision is:

Options

A. `2:1`
B. `1:2`
C. `4:1`
D. `3:1`

Answer

a

Explanation

Here height of fall `h_1=10m`
and height of rebound `h_2=25m`
Let the velocity of strike be `v_1` and that of rebound be `v_2` then
`(v_1)/(v_2)=sqrt((2gh)/(2gh_2))=sqrt((h_1)/(h_2))`
=`sqrt((10)/(2.5))=2//1`
`v_1:v_2: :2:1`