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Centripetal Force Vs. Centrifugal Force

Ever swirled a stone at the end of a rope or seen a roller coaster performing a 360-degree rotation? I am sure you must have witnessed such things and in all such phenomena, 2 forces play a very important role to make those things perform in the way they do.

These forces are the ‘Centrifugal Force’ and the ‘Centripetal Force’. Many times we get confused between these so-similar-looking names and wonder which one is what and also what are the differences between these two?

Centripetal force is defined as, “the force that is necessary to keep an object moving in a curved path and that is directed inward toward the center of rotation,” while centrifugal force is defined as “the apparent force that is felt by an object moving in a curved path that acts outwardly away from the center of rotation,”

We are going to discuss just that and the role each one of these forces plays in this article. So, let’s dive into it.

Importance Of centrifugal and Centripetal Forces

Understanding and applying these forces can help with a variety of situations in everyday life.

One such example is the construction of roadways. Application and understanding of these forces can help to avoid skidding. Their understanding also helps in improving traction on highway curves and access ramps.

The forces were also crucial in the development of the centrifuge. By spinning the test tubes at high speeds, the centrifuge separates particles floating in fluid.

Centrifugal force could one day be used to create artificial gravity for space stations and ships.

Centrifugal Force:

When an object is performing a circular motion, the pseudo force that acts at the time of rotation and is directed away from the center is called the centrifugal force. We can notice this force when we change our viewing reference from inertial to rotating reference frame.

The centrifugal force is calculated by using the following formula:

F = -mv2/r

where,

‘F’ is the centrifugal force

‘m’ is the mass of the object

‘v’ is the tangential velocity of the object (while performing circular motion)

‘r’ is the distance between the center of the rotation and the object.

Examples (Centrifugal Force):

  1. Assume you are holding a bucket that has some amount of water in it. If you rotate your hand which is holding the bucket in a circular motion fast enough, the water in the bucket will remain intact even after 1 full rotation is complete. Why didn’t the waterfall to the ground when the bucket is at the topmost position of the rotation circle? This is due to the centrifugal force of the amount of water as a whole which acted in the outward direction in this case.
  2. We all have sat in a merry-go-round when we were small. Whenever the merry-go-round used to be in motion, we used to feel a force pushing us away from the center. The more the spinning speed, the harder it would get to stay in that position. This force that was mysteriously pushing us away from the merry-go-round is the centrifugal force.

Centripetal Force:

In an object performing the circular motion, the force that is acting perpendicular to the object’s tangential velocity and is directed towards the center of the curved path or circular path is called the centripetal force.

The centripetal force is calculated using the following formula:

F = mv2/r

Where the notations are the same as mentioned in the centrifugal force’s formula, the difference of sign comes into play as both the forces are opposite to each other.

Examples (Centripetal Force):

  1. Imagine a stone tied to the end of a rope and is swirled around in the air. The centrifugal force which depends on the mass and velocity of the stone and the radius of rotation acts on the stone. In counter to that, the centripetal force acts in the form of tension which acts towards the center that gets built in the rope due to the swirling.
  2. We have sent a lot of satellites to orbit our earth and our planet itself orbits the sun. This phenomenon is caused by one of the inevitable forces in our universe which are gravitation which is caused by any object which has a significant mass. Here too, the gravitational pull of earth for the satellites and of the sun for the earth can be recognized as the centripetal force acting for the circular motion happening here.

Differences between Centrifugal and Centripetal Force:

  • The centripetal force acts towards the center of rotation whereas centrifugal force acts away from the center.
  • The magnitude signs are different for both the forces as they act totally opposite to each other.
  • Centripetal force is a real force whereas centrifugal force is a pseudo force.
  • Centripetal force can be seen in an inertial reference frame whereas centrifugal force can be witnessed in the rotating reference frame.

So, centrifugal and centripetal forces act on anybody which is in a circular motion and they have opposite and equal magnitudes provided the rotating body is following the same path again and again.

Centripetal Force and Centrifugal Force in Tabular Form

 Centripetal ForceCentrifugal Force
1.It is directed along the radius towards the center of the circle.It is directed along the radius away from the center of the circle.
2. It is a real forceIt is a pseudo force
3. It is considered in an inertial frame of referenceIt is considered in a non-inertial frame of reference.
4. In vector form it is given by $$\vec{F}=-\frac{mv^2}{r}\hat r$$In vector form it is given by $$\vec{F}=-\frac{mv^2}{r}\hat r$$
5.Example:- Moon revolves around the earth in a circular orbit. Here in this case the necessary centripetal force is provided by gravitational force between the moon and earthExample: The bulging of the earth at the equator and the flattening of the earth at the poles is due to centrifugal force acting on it.

Conclusion

In conclusion, centrifugal force is an apparent force that is not a real force, despite the fact that it is closely related to centripetal force, which is an actual force.

The primary distinction between the two is their direction, which is also related to each force’s frame of reference. Gravity, which keeps the moon in orbit, is an example of centripetal force.

There are various examples of centrifugal force, such as the force felt by children as they spin on a merry-go-round.

Frequently Asked Questions

What is Centripetal force?

It is defined as, “the force that is necessary to keep an object moving in a curved path and that is directed inward toward the center of rotation,”

What is Centrifugal force?

It is defined as, “the apparent force that is felt by an object moving in a curved path that acts outwardly away from the center of rotation,”

Give examples of Centripetal force.

Revolution of the moon around earth, rollercoaster, shot put and hammer throw are some of the examples where we find the applications of centripetal force

Give examples of Centrifugal force.

Centrifuge machines and washing machines are the examples of applications of centrifugal force.

Does centripetal force increase with speed?

Yes centripetal force increases with the increase in speed of the object. From the formula of centripetal force 
$F=mv^2/R$
We can easily see that when the speed of the object increases, the centripetal force experienced by it also increases.

Does centripetal force increase with radius?

No, the centripetal force does not increase with the increase in the radius. From the formula of centripetal force 
$F=mv^2/R$
We can easily see that when the radius of the turn of the particle increases, the centripetal force experienced by it decreases.