Centripetal and Centrifugal Force: Definition, Formula, Differences and Real-Life Examples

Centripetal and centrifugal forces are two of the important forces that help us explain circular motion. From a car taking a turn to the Moon moving around the Earth, these forces play an important role in everyday life. Have you ever noticed that you feel pushed outward when a car suddenly takes a turn? Or wondered what keeps the planets moving around the Sun? The answers lie in centripetal and centrifugal force.

This article provides insights into centripetal and centrifugal force, their formulas, real-life examples, and the difference between them.

Table of Contents

• What is Centrifugal Force, Formula and SI Unit
• What is Centripetal Force, Formula and SI Unit
• Difference Between Centripetal Force and Centrifugal Force
• Examples of Centripetal and Centrifugal Force in Real Life

What is Centrifugal Force, Formula and SI Unit

Centrifugal force is the sensation of being pushed outward because an object tends to continue moving in a straight line due to its inertia. In simple words,

“ Centrifugal force is an apparent outward force felt by an object moving in a circular path. It is a pseudo or fictitious force that creates the sensation of being pushed away from the centre due to the object's inertia.”

Now, let's use the same example of the bucket of water. When the bucket is rotated in a circle, the water seems to be pushed outward against the bottom of the bucket. This outward effect is called centrifugal force.

Interestingly! There is no real outward force acting on the water. Because of inertia, the water tends to continue moving in a straight line. The feeling of an outward push is what we call centrifugal force.

Interestingly! There is no actual outward force acting on you. Your body tends to continue moving in a straight line because of inertia, as explained by Newton's first law of motion. The feeling of being pushed outward is what we call centrifugal force.

Centrifugal Force Formula and SI Unit

The formula for centrifugal force is:

F=mv2r

Where F is centrifugal force, m is the mass of the object, v is the velocity of the object, and r is the radius of the circular path.

Although this formula is the same as that of centripetal force, the direction is different. Centripetal force acts towards the centre of the circle, whereas centrifugal force appears to act away from the centre.

The SI unit of centrifugal force is newton (N).

What is Centripetal Force, Formula and SI Unit

Centripetal force is the force that keeps an object moving in a circular path. It always acts towards the centre of the circle. The word centripetal means "centre-seeking."

“Centripetal force is the force that acts towards the centre of a circular path and keeps an object moving in a circle instead of a straight line.”

Have you ever seen a bucket filled with water being swung in a vertical circle? 

Even when the bucket is upside down, the water does not fall out if it is moving fast enough. This happens because a force keeps the bucket and water moving in a circular path. This inward force is called centripetal force. 

In simple words, whenever an object moves in a circular path, there must be a force acting towards the centre of the circle. Without this force, the object would move in a straight line instead of following a circular path.

Centripetal Force Formula and SI Unit

The formula is,

 Fc=mv2r
Where,  Fc is centripetal force (N), m is mass of the object (kg), v is velocity of the object (m/s), and r is radius of the circular path (m).

The SI unit of centripetal force is newton (N).

Interestingly! The formula shows that the centripetal force increases when the speed of the object increases.

For example,

• If the speed becomes twice, the centripetal force becomes four times greater.
• If the radius increases, the centripetal force decreases.

Do you know? Just like other forces, centripetal force is also measured in newtons (N). 

Difference Between Centripetal Force and Centrifugal Force

Although both forces are related to objects moving in a circle, they differ in their direction, nature, and frame of reference.

Feature	Centripetal Force	Centrifugal Force
Meaning	The force that keeps an object moving in a circular path acts towards the centre.	The apparent force that seems to push an object away from the centre of the circular path.
Direction	Directed towards the centre of the circle.	Directed away from the centre of the circle.
Nature	A real force caused by interactions such as tension, gravity, or friction.	A pseudo or fictitious force caused by the inertia of the object.
Frame of Reference	Observed from an inertial (stationary) frame of reference.	Observed from a non-inertial or rotating frame of reference.
Cause	Required to continuously change the direction of the object and keep it moving in a circle.	Arises because the object tends to continue moving in a straight line due to inertia.
Function	Keeps an object on a circular path.	Produces the feeling of being pushed outward.

Examples of Centripetal and Centrifugal Force in Real Life

The effects of centripetal and centrifugal force can be observed in many everyday situations. In most cases, these two forces are discussed together because one force keeps an object moving in a circle, while the other is the apparent outward effect felt by the object.

• Merry-Go-Round: When a child sits on a spinning merry-go-round, the force towards the centre keeps the child moving in a circle. This is the centripetal force. However, the child feels as if they are being pulled outward, which is the effect of centrifugal force.
• Washing Machine Spinner: During the spinning cycle of a washing machine, the drum provides the centripetal force that keeps the clothes moving in a circular path. The water appears to move outward through the small holes of the drum due to the effect of centrifugal force.
• Roller Coaster Loop: When a roller coaster moves through a loop, the track exerts a centripetal force on the riders, keeping them on the circular path. At the same time, riders often feel as if they are being pushed outward because of centrifugal force.
• Satellite Orbiting the Earth: The gravitational force between the Earth and a satellite acts as the centripetal force, keeping the satellite in orbit. From the rotating frame of the satellite, an apparent centrifugal force seems to balance this inward pull.
• A Car Taking a Circular Turn: When a car moves around a curved road, friction between the tyres and the road provides the centripetal force. Passengers inside the car feel pushed towards the outer side of the turn, which is the effect of centrifugal force.
• Amusement Park Rides: Many spinning rides in amusement parks work on the principles of centripetal and centrifugal force. The ride continuously pulls the riders inward, while the riders feel an outward push during the motion.
• Rotating Ceiling Fan: The blades of a ceiling fan move in a circular path because the motor provides the centripetal force. If a blade becomes loose, it flies off tangentially because the centripetal force is no longer acting on it.
• Swing Ride in an Amusement Park: In a swing ride, the chains pull the seats inward and provide the centripetal force. The riders feel as if they are being pushed outward due to the effect of centrifugal force.
• Earth Revolving Around the Sun: The gravitational force between the Earth and the Sun acts as the centripetal force that keeps the Earth in its orbit. From the Earth's rotating frame, an apparent centrifugal force seems to act outward.
• Satellites Orbiting the Earth: Artificial satellites remain in orbit because the Earth's gravity provides the centripetal force. The outward effect felt in the rotating frame is called centrifugal force.
• Rotating Salad Spinner: A salad spinner rotates rapidly to remove water from vegetables. The bowl provides the centripetal force, while the water moves outward through the holes because of the effect of centrifugal force.
• Mixing Machine or Blender: Inside a blender, the rotating blades create circular motion. The ingredients move outward against the container walls due to the effect of centrifugal force, while the container provides the required centripetal force.
• Ferris Wheel: Passengers on a Ferris wheel move in a circular path because the wheel provides the centripetal force. At certain points during the ride, passengers may feel an outward pull due to the effect of centrifugal force.

These examples show that centripetal and centrifugal forces are closely related and help explain many types of circular motion that we experience in everyday life.

In this article, we learned that centripetal and centrifugal forces are closely related to circular motion. Centripetal force pulls an object towards the centre of the circular path, whereas centrifugal force appears to push it away from the centre.