Jerry Bailey and Physics

[ninetoone]

Common misunderstandings:

Centripetal force should not be confused with centrifugal force. The centrifugal force is a fictitious force that arises from being in a rotating reference frame. To eliminate all such fictitious forces, one needs to be in a non-accelerating reference frame, i.e., in an inertial reference frame. Only then can one safely use Newton's laws of motion, such as F = ma.

Centripetal force should not be confused with central force, either. Central forces are a class of physical forces between two objects that meet two conditions: (1) their magnitude depends only on the distance between the two objects and (2) their direction points along the line connecting the centres of these two objects. Examples of central forces include the gravitational force between two masses and the electrostatic force between two charges. The centripetal force maintaining an object in circular motion is often a central force.