# What is fictitious force?

[SOLVED] What is fictitious force?

Hi.

I was wondering if someone would be able to explain to me what is meant by fictitious force? I know that it is a force that acts on masses in a non-inertial frame of reference. That is to say, the motion of the car from the view of the driver, for example. But what makes it "fictitious"?

Thanks. :)

## Answers and Replies

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"Real" forces have actors, something that exerts the force; "fictitious" forces do not. Take an example of a car racing around a circular track. There is a real centripetal force acting on the car: The road exerts a frictional force on the car. The road is the actor.

Fictitious forces are just artifacts of viewing things from a non-inertial reference frame, required to make use of Newton's laws. Viewed from the frame of the car, there's a centrifugal force acting outwards. Don't bother asking what exerts that force, since it's not a real force.

Does that help a bit?

I think so...

So its fictitious because the force is not placed directly on the object, but is in a manner of speaking a by-product (in your example, of the centripetal force acting on the car)?

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So its fictitious because the force is not placed directly on the object, but is in a manner of speaking a by-product (in your example, of the centripetal force acting on the car)?
Yup, that sounds about right. I think Pseudo-forces (that is how I heard them to be called most often) as accounting for the acceleration. What I mean by this is that acceleration happens when you don't have balanced forces, so to pretend that you have no acceleration when you are in the non-inertial frame, you have to add this fictional pseudo-force to cancel the acceleration.

Ah! I understand! Thank you both for your help! :D