Introduction: A Demo for Circular Motion
This is an Instructable on how to demonstrate that circular motion requires the application of a constant force directed toward the center of the circle, and the vectors that accompany that motion. First we create the apparatus to demonstrate the principle, then, we will discuss how it is to be used.
A rubber ball (a high bouncing ball works too, get a large one)
A thick string, 3 or 4 feet long
A size E crochet hook
A pair of pliers
Using the counter top, apply force to the base of the crochet hook forcing the tip through the center of the rubber ball and out the other end.
Grab the thick string, with the end of the hook. Use the pliers to pull the hook back through the ball taking the thick string with it.
When the hook is out of the ball and the loop is out, stop. The rubber (or high bouncing ball) will close in around the string and hold it in place.
If you used nylon string, after you cut off the 3/4 foot length, use the lit candle to melt the end. If you don’t want to do that, tie a slip knot in the end.
Now you have the apparatus completed.