Uniform Circular Motion

Do this! Right now, take a break from what you are doing, get up from your seat, and try this. All you will need is a ball of some sort and a place where you can move around in a reasonably large circle of about a ten foot radius. This actually works quite well with a bowling ball, but a basketball or soccer ball should work as well. 

Your job is to gently kick the ball so it moves at a constant speed, but travels along a circular path. Try this and make note of what you see.