Eli5, how does gears work?

Question

For example, I understand gears work with ratio (different sizes) that changes the speed of a car, but how exactly – & why does it do that?

Also, how does it connect with gears + revolutions per min (RPM)?

Thanks!

In: Engineering

Answer 1

Imagine you have a bunch of cylinders that you roll down a hill. The little cylinders move really fast quickly and the big cylinders take a while to gather momentum but once they do they can go way faster than the small cylinders. Gears are a way that you can cheat and do both.