Question

A stone is dropped from the edge of a roof. The roof is 19.6m high from the ground. (Take g= 9.8 m/s2 ) (a) How long does it take to reach the ground? (b) Calculate the velocity with which an object would hit the ground.​

Answer 1

Given that

Initial velocity

u = 0

Tower height = total distance = 19.6m

g = 9.8 m/s2

Find out

Final velocity just before touching the ground.

Solution

Let us solve using third equation of motion

v2 = u2 + 2gs

v2 = 0 + 2 × 9.8 × 19.6

v2 = 384.16

v = √(384.16)

v = 19.6m/s

Answer

Final velocity just before touching the ground = v = 19.6m/s