Question

A stone is thrown upwards with a speed '$u$' from the top of a tower. It reaches the ground with a velocity '$3u$'. Find the height of the tower.

• A. $\sqrt{3}$
• B. $\frac{2u^2}{g}$
• C. $\frac{3u^2}{g}$
• D. $\frac{4u^2}{g}$

Answer 1

The correct option is D $\frac{4u^2}{g}$

$v^2=u^2+2gh$

$h=\frac{v^2-u^2}{2g}=\frac{9u^2-u^2}{2g}=\frac{4u^2}{g}$