Question

A ball is thrown vertically downward with a velocity of 20m/s from the top of a tower. It hits the ground after some time with a velocity of 80m/s. The height of the tower is : (g = $10m/s^2$)

• A. 360 m
• B. 340 m
• C. 320 m
• D. 300 m

Answer 1

Answer: (D)

300 m

Answer 2

Using, $v^{2}=u^{2}+2gh$
Given, $V=80m/s$ and $u=20 m/s$
$h=\frac{v^{2}-u^{2}}{2g}$
$=\frac{6400-400}{20}$
$=300\,m$