FearOfPhysics.com: Things That Spin

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Things That Spin

Take a look at these two red balls, both of which are moving.


Moving along a straight line.

Moving in a circle.

A lot of what is discussed in Physics has to do with straight line motion, like the ball on the left. Cars driving down the road, things falling to the ground, etc. In fact, even a Jumpshot, although curved looking, is a combination of up/down and left/right straight line motion.

Straight line just makes more sense: something moves in a straight line because, at some point, something pushed it in that direction! For instance, if a car goes straight down the road, it's because the engine is pushing it that way.

When things start to move in circles, like the ball on the right, the concepts get a little trickier. It's suddenly not so obvious exactly why things behave the way they do.

Hmm. Here are a couple of examples for you to try.

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