A body freely falling from the rest has velocity `v` after it falls through a height `h` the distance it has to fall down for its velocity to become double is

Options

A. 8 h
B. 6 h
C. 4 h
D. 5 h

Answer

C

Explanation

`upsilon=sqrt(2gh)` or `upsilon prop sqrt(h)`
`rArr (upsilon_(1))/(upsilon_(2))=sqrt((h_(1))/(h_(2)))rArr ((upsilon_(1))/(upsilon_(2)))^(2)=(h)/(h_(2)) " " {because h_(1)=h}`
`rArr ((upsilon)/(2upsilon))^(2)=(h)/(h_(2)) " " {{:(because upsilon_(1)=upsilon),(therefore upsilon_(2)=2upsilon):}}`
`rArr h_(2)=4h`