"188.8.131.52.1. We have ignition! We have lift-off!" You feel yourself being pushed into your seat as the space shuttle heads into the sky. The push you feel is called the G-force.
Astronauts-in-training feel the same force when they train in a centrifuge. This is a machine which whirls them round in a cabin at the end of a long arm and simulates the feeling at lift off.
This force that appears to be acting outwards on the person has been conveniently called "centrifugal force". In reality, centrifugal force is a fictitious force.
According to Newton's First Law of Motion,
Any object in a state of rest or of uniform linear motion will remain in such a state unless acted upon by an unbalanced external force.
So, if you are standing on a rotating merry-go-round in a playground, the natural tendency is for you to continue moving in a straight line at a tangent to the merry-go-round.
- What prevents you from being flung off?
Not centrifugal force but the force you exert in your arms pulling yourself inwards as you hold on to the railing.
- What prevents the astronaut-in-training from being thrown against the front (or sides) of the cabin?
Not centrifugal force but the force exerted by the seat belts.
"George Files" by Parenting the Next Generation