Question

A stone is dropped(free fall) from the top of the tower. It takes 4 seconds to reach the ground. Find the height of the tower.

Answer 1

In this case we will use second equation of motion,

S = ut + (1/2) at^2

where, s= distance travelled (height)

u= initial velocity (here u=0)

a= acceleration due to gravity = (9.8m/s^2)

t= time taken = 4 s

s = 0×4 + (1/2) × 9.8× 4 × 4

= 156.8 /2 = 78.4 m

Therefore,
Height of tower = 78.4 m