# Centripedal & Centrifugal force

1. Nov 9, 2005

hi,
what is difference between Centripedal & Centrifugal ? One is in inertial frames and the other in rotating frames? one is 'true' force and the other is fictitious force?

thanks

2. Nov 9, 2005

### dextercioby

1.It's "centripetal", not "centripedal".

2. Changing reference frames from inertial to noninertial frames usually involves the appearance of effects such as centrifugal forces, Coriolis forces.

There are no such things as "fictitious forces". Any nonzero acceleration is a frame of reference means a nonzero force is present.

Daniel.

3. Nov 9, 2005

### Staff: Mentor

When viewing circular motion from an inertial frame, one finds a centripetal force producing the acceleration. Centripetal force is a "real" force, since it requires a real agent (something that exerts the force).

Viewed from the rotating non-inertial frame, Newton's laws must be modified by the additional of "fictious" (better called "inertial") forces like centrifugal force. Centrifugal force is "fictitious" in the sense that it is entirely due to viewing things from a noninertial frame; there is no agent exerting the centrifugal force. But the effect is very real.

4. Nov 9, 2005