# Invalidation of Newton's law

1. May 3, 2010

### astro2cosmos

why the newton's law of motion are only valid in inertial frame of reference, not in non-inertial frame? since force like Coriolis force are not considered for these laws.

2. May 3, 2010

### Staff: Mentor

The Coriolis force is an example of a fictitious force that needs to be added when viewing things from a rotating frame in order to apply Newton's laws. Fictitious forces only appear in accelerating reference frames.

3. May 3, 2010

### tiny-tim

Hi astro2cosmos!

In a non-inertial frame, Newton's laws of motion are valid if we allow fictitious forces such as centrifugal force and Coriolis force …

that is what the fictitious forces were invented for, to make Newton's laws work!