A stone thrown upward with a speed u from the top of the tower, reaches the ground with velocity 3u. The height of the tower is

Question

A stone thrown upward with a speed u from the top of the tower, reaches the ground with velocity 3u. The height of the tower is (A)  (8u2/g)  (B)  (3u2/g)  (C)  (4u2/g)  (D)  (5u2/g)

Tardigrade Admin · Accepted Answer

v2=u2+2gh or (3u)2=u2+2gh or h=(4u2/g)

Q. A stone thrown upward with a speed $u$ from the top of the tower, reaches the ground with velocity $3 u$ . The height of the tower is

$\frac{8 u ^{2}}{g}$

$\frac{3 u ^{2}}{g}$

$\frac{4 u ^{2}}{g}$

$\frac{5 u ^{2}}{g}$

$v^{2} = u^{2} + 2 g h$ or $(3 u)^{2} = u^{2} + 2 g h$ or $h = \frac{4 u ^{2}}{g}$

Q. A stone thrown upward with a speed u from the top of the tower, reaches the ground with velocity 3u. The height of the tower is

g8u2​

g3u2​

g4u2​

g5u2​