We see it in the spin cycle of a
washing machine or when children ride on a merry-go-round.
Centrifugal force is
often confused with its counterpart, centripetal force, because
they are so closely related. Centrifugal force is defined as the
apparent force that is felt by an object moving in a curved path
that acts outwardly away from the center of rotation. It is more
inertia than a force. An example of centrifugal force is the
earth's revolution around the sun. Another is passengers feeling
pushed outward on a merry-go-round.
Centripetal force is
defined as the force that is necessary to keep an object moving
in a curved path and that is directed inward toward the center
of rotation. If you are in a spacecraft orbiting the earth, the
centripetal force is the force of gravity. Another example is
spinning an object on a string. The tension on the rope pulls
the object in toward the center.
Centripetal force and
centrifugal force are the same force, just in opposite
directions, because they are experienced from different frames
of reference.
Centripetal force is an
actual force; centrifugal force is an apparent force. In other
words, when twirling a mass on a string, the string exerts an
inward centripetal force on the mass, while mass appears to
exert an outward centrifugal force on the string.