What is centrifugal force?
Centrifugal force is called a virtual force. Because when an object revolves around in a circle, it feels that someone or something is pushing it outwards from the center. Actually no one is pushing, the force is felt from somewhere else.
A daily-life example of centrifugal force
Suppose that you are sitting in a bus. At this time the bus starts to turn right/left, it starts moving in a circle. The upper portion of your body will be tilted, it will be pushed outwards from the center. This happens basically due to inertia. According to Newton’s 1st law of motion, if no force is applied on you from outside, then you’re supposed to move in a straight line. Since the lower portion of your body is rigidly connected with the bus, that’s why it starts turning when the bus does. But the upper portion of your body is fairly free, that’s why it tends to move in a straight line as before. This is the reason why your upper body tilts and seems to move away from the center of the circular path.
Suppose you took a window seat and your upper body gets in contact with that of the bus due to the tilting effect and the feeling of ‘being pushed away’. In that case the body of the bus will put force on your upper body and thus make it move in a circular path (this force is basically centripetal force which is mandatory if a body wants to revolve in a circle). Although you will feel that someone or something is pushing you to make your upper body being pressed against that of the bus.
The force you thought was centrifugal is actually centripetal
So from the above discussion it is evident that no one or nothing applies a force on you from the center of the circular path. You just feel a centripetal force which is supplied from some other source you didn’t even think of. In the above example, the centripetal force is supplied by the body of the bus. According to Newton’s 3rd law of motion, your body also applies a force on the bus. These two forces are equal in magnitude, but acting in opposite directions. Keep in mind that the two forces mentioned in Newton’s 3rd law of motion applies on two different objects, not on a single object. Had these two forces been acting on the same object, they would eventually cancel each other.
So now you know why centrifugal force is called virtual force. When you move in a circle, you seem to feel it, you feel that something is pushing you away from the center. Actually nothing of this sort is happening. A force is definitely being acted upon your body, but it is the centripetal force, NOT centrifugal.
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