Quote:
Originally Posted by Champcar 
I must be a retard, I know what a centrifuge is but i remember the bucket full of water from middle school science and calling it centrifical force (unless i cant spell) but I had NEVER heard of centrifugal.
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Think back to that bucket. Imagine a man spinning around holding a bucket half full of water. His arm is outstretched, parallel to the ground, and the bucket is perpendicular to the ground. In other words, if the bucket were at rest, the water would pour out onto the ground. But it doesn't. It remains "suspended" at the bottom of the bucket.
Besides gravity, 2 forces act on the water and the bucket. The first we know from an introductory study of Newton. A body at rest tends to remain at rest, and a body in motion tends to remain in motion, until acted upon by some outside force. We usually refer to this tendancy as inertia. The bucket of water wants to continue to move in the direction in which it is currently moving. If you could freeze-frame the motion, the direction it wants to travel is exactly perpendicular to your outstretched arm.
So then, why does it not travel in this direction? Because your outstretched arm also imparts a force to the bucket in the direction of the center of this spinning man and bucket combo. Your arm pulls the bucket toward your body. It is this force that transforms the straight line, unaccelerated motion of the bucket, into a circular motion. This force is known as centripetal force.
Wanna know what happens without centripetal force? Let go of the bucket. Then it's all inertia and gravity.
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