Question

To estimate the height of bridge over a river stone is dropped freely in the river from the bridge. The stone takes 2 seconds to touch the water surface in the river. Calculate the height of the bridge from the water level?

Answer 1

s=ut+1/2at²
s=0(t)+1/2g(2)²
=9.8*2
s=19.6m.
Therefore, the height is 19.6m.
Hope this will help u.

Answer 2

g = + 9.8 ms^-2

t = 2 second

u = 0

s = ?

Using Equation of Gravitation

${\implies s = ut + \dfrac{1}{2}gt^{2}}$

${\implies s = 0 + \dfrac{1}{2}\times 9.8\times 2^{2}}$

= 19.6 m