Question

A body freely falling from the rest has a velocity ${}^{\prime }{v}^{\prime }$ after it falls through a height ${}^{\prime }{h}^{\prime }$. The distance it has to fall down for its velocity to become double, is

• A. $6h$
• B. $8h$
• C. $4h$
• D. $2h$

Answer 1

The correct option is C $4h$

Let at point $A$ initial velocity of body is equal to zero
For path $AB:$
$v^2=0+2gh....\left(i\right)$
For path $AC:$
$(2v{)}^2=0+2gx$
$4v^2=2gx....\left(ii\right)$
Solving $\left(i\right)$ and $\left(ii\right)$ $x=4h$