Question

A stone is thrown vertically upwards with an initial velocity "U" from the top of a tower reaches the ground with a velocity "3U". what is the height of the tower?

Answer 1

Let h be the height of the tower.⇒ v2=u2+2aS
⇒ (−3u)2=u2+2(−g)(−h)

⇒ 9u2=u2+2gh

⇒ 8u2=2gh

⇒ h=8u2/2g

⇒ h=4u2/g


I hope its helps.you...