Visualizing Motion during a Free Fall - Understanding Freefall

Last Updated on Jan 23, 2025

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Have you ever dropped an object, let's say, a ball from a significant height, like a tall building? The ball's movement from the point of release until it hits the ground is what we call free-fall motion.

Defining Free Fall
We describe free fall as a scenario where an object is solely under the influence of the earth's gravity. As a result of this external force, the object's motion accelerates. This acceleration is commonly referred to as acceleration due to gravity. So, how do we determine the value of acceleration due to gravity during free fall? We will need to make an assumption that the height from which the object falls is negligible compared to the earth's radius.
Force acting during free fall = Force of gravitation between earth and the object
Assuming,
\(\begin{array}{l}F = \frac{GMm}{R^2}———-(1)
\end{array} \)
Based on Newton’s second law,
Freefall acceleration or acceleration due to gravity is symbolized by ‘g’.
By equating equations (1) and (2),
Here, M = mass of the earth and R = radius of the earth
One might wonder if 'G', the Universal Gravitational Constant, remains the same everywhere. Does the same hold true for 'g'? As per equation (3), 'g' depends on the dimensions of the body, i.e., its mass and radius. Therefore, it varies from place to place. However, during free-fall motion, the acceleration remains constant, allowing us to use the equations of motion. We just need to replace the acceleration in all equations with 'g'.
For instance, v = u + gt

Frequently Asked Questions

What is meant by freefall?

Freefall can be defined as a scenario when an object is moving only under the effect of the Earth’s gravitational pull. As external force is exerted on the object, the motion will be constantly accelerated. This is known as freefall acceleration.

What is meant by weight?

Weight is the measure of the force of gravity acting on a body. The formula for weight is given by: w = mg.

What is weightlessness?

Weightlessness is a condition of free-fall in which the gravity is cancelled by the inertial force arising from orbital flight or other gravity-negating situations.

What is inertia?

Inertia is a scalar quantity which is the measure of the resistance exerted by an object to any change in velocity.

What is acceleration?

Acceleration is defined as the rate of change of motion of a body. In other words, the measure of the rate of change in its speed along with direction with respect to time is called acceleration.

What is linear acceleration?

The motion of the object can be linear or circular. Thus, the acceleration involved in linear motion is called linear acceleration.

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