Question

A ball is thrown vertically upwards from the top of a tower with an initial velocity of 30m/s. If the

height of the tower is 135m, calculate the time it would take the ball to reach the ground from

the time it is thrown. (g = 10m/s2

).
​

Answer 1

Taking downward direction to be positive.

Initial velocity u=−10 m/s

Final velocity v=30 m/s

Let the height of the tower be H.

Acceleration a=g=10 m/s ^2

Using v^2 −u ^2 =2aH

∴ 30 ^2

−(−10) ^2

=2×10 ×H

$\bf \: ⟹ H=40 m$

$\bf \red{Khushi}$