Work occurs when movement occurs as a result of force being applied. Work can be hard! It can be made easier by using a machine. A machine lets you use less force but over more distance.
Simple machines include pulleys, wheels and axles, levers and inclined planes.
1) How do machines make work easier?
2) How does a pulley reduce the force needed to produce work?
3) Can you think of any examples of simple machines in your house that were not listed in the book?
4) If those are simple machines, what do you think complex machines are? Can you think of any examples?