Wheels help people do work in two ways. First, like levers or inclined planes, wheels allow you to do something easy for a longer time, instead of doing something hard for a shorter time. If you turn a large wheel fixed to an axle, the axle will also turn. You can turn the large wheel easily.But the axle will go around a much shorter distance then the big wheel, but with more force. So you can use a wheel to create a mechanical advantage - you can turn something heavy, by spinning a large wheel attached to an axle that is attached to the heavy thing. That's how a pencil sharpener works.