Question

The bird in fig A drops the stone from a height of 88 m above the
water surface. Initially, the stone has zero vertical velocity. How
long will it take the stone to reach the surface of the pond?
Assume air resistance is negligible.

Answer 1

Solution

The time taken by stone to reach on the surface of pond

is second equation of motion

$S=ut+\frac{gt^2}{2}$

Initial velocity is zero

g=9.8m/s²

So

Time taken by stone is

$t=\sqrt{\frac{2S}{g}}$

$t=\sqrt{\frac{2\times88}{9.8}}$

t=4.29 sec.