Question

What is meant by free fall? A ball is dropped from the roof of a building. It takes 10 seconds to reach the ground. Find the height of the building. (g = 9.8 m/s2 )

Answer 1

Free fall is a motion under gravity. There is no other force acting on the object other than the force of gravity.

Let the height of the building be H.

Time taken to reach the ground (t) = 10 seconds

Initial velocity (u) = 0 m/s

Acceleration due to gravity = 9.8 m/s^2

Using the second equation of motion:

$H = ut + \frac{1}{2} \times a \times t^2$

$H = 0 + \frac{1}{2} \times 9.8 \times 10^2$

H = 490 m

Hence, the height of the building is 490 m

Answer 2

Hello user this is your answer for the question:--
The fall of the body from a height towards the ground under gravitational force and with no other force acting on it is called free fall.

t = 10 s
g = 9.8 m/s2
u = 0 m/s


s = ut+1/2at2
(or)
s = ut+1/2gt2
= 0×10+1/2×9.8×10×10
= 0+1/2×980
= 0+980/2
= 0+490
= 490
s = 490 m

Hope you understood.