# Visualizing Motion During a Free Fall, What is Free Fall? (For CBSE, ICSE, IAS, NET, NRA 2022)

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# Visualizing Motion During a Free Fall

When you drop a ball, let՚s say from top floor of a building, it reaches the ground the ball is said to be in a free fall motion.

## What is Free Fall?

• Free fall: it is defined as a situation when a body is moving only under the influence of earth՚s gravity.
• Though, external force is acting on the ball the motion will be accelerated.
• This free fall acceleration is also known as acceleration due to gravity. Let us find the value acceleration due to gravity during free fall.
• For finding this we take one assumption that the height from which the ball is dropped is very small as compared to the radius of the earth.

We have assumed

According to Newton՚s second law,

Free fall acceleration or acceleration due to gravity is represented by ‘g.’

… (2)

Using equation (1) and (2) ,

Where,

M = mass of earth R = radius of earth

• Now the next that comes to mind is that we have already seen is ‘G’ i.e.. , Universal Gravitational Constant.
• From equation (3) we can see that g depends on the dimension of the body i.e.. , mass and radius. Hence it will not be same everywhere.
• Also, as the acceleration remains constant during free fall motion, so we can use equations of motion.

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