| A | B |
|---|
| force | a push or pull |
| motion | a change in position |
| work | when a force moves an object |
| speed | measure of how fast something moves over a certain distance |
| simple machine | a tool that helps people do their work |
| inclined plane | a flat surface that is higher on one end than the other |
| lever | a bar that moves on or around a fixed point called a fulcrum |
| fulcrum | where the lever rest |
| screw | an inclined plan that is wrapped around a center rod |
| wheel and axle | a wheel with a rod attached to the center of it |
| pulley | a wheel with a rope around it for lifting things |
| A ____ can change the _____ of an object | force, motion |
| gravity | acts on all things. It can change the speed/direction of a moving object |
| friction | exist between two objects that touch |
| If you toss a ball up, it comes back down | example of gravity |
| Rough surfaces have more__ than smooth surfaces | friction |
