circular motion and centripetal force?

Question

What is circular motion and centripetal force? What causes them to have this motion?

Answer 1

Ahh... something moving around a point in space with an angular velocity?

I have no idea of what causes 'them' to have this motion.

Answer 2

When motion of a body is in two dimension and distance of the body from a fixed point (called center of circular path) remains constant, the motion of body is circular motion.

In circular motion , the direction of motion is continuously changing, if speed remains constant, it is called uniform circular motion

Circular motion is accelerated motion , if speed is constant then direction of acceleration is towards the center hence the acceleration is called centripetal acceleration

Centripetal acceleration is caused by a force acting towards the center and the force is called centripetal force.

If body moves on circle and speed is changing then direction is inclined to radius, the inclination depends on change in speed

A force acting towards the center is necessary for circular motion

Answer 3

I can cause an object that i hold, to have a completely random motion....

its something similar, a constant tangential force acting from a distance on an object in simple linear motion:
balanced - path is a circle / ellipse..
more/less path is a inward or outward spiral..

and centrifugal vs centripetal:
centripetal = force toward center of motion path, that binds the moving object in its path
centrifugal = force caused by objects motion, that tends to cause object to fly off if the centripetal force weakens e.g. a string breaking...

http://en.wikipedia.org/wiki/Circular_motion
http://en.wikipedia.org/wiki/Centripetal