1. The unit used to express work is the______________

2.A______________ is an inclined plane that is wrapped in a spiral.

3.______________ is the rate at which work is done.

4.____________ occurs when a force causes an object to move in the direction of the force.

5. The work you do on a machine is called the work________

7.The mechanical____________ of a machine compares the input force with the output force.

9. When two kinds of pulleys are used together, the system is called a ______________

11. A__________________ is a device that helps make work easier by changing the size or direction of force.

12. A____________ is a double inclined plane that moves

13. Machines that are made up of two or more simple machines are called _____________ machines.

14. A_____________ is a simple machine consisting of two circular objects of different sizes

16. The work done by a machine is called the work __________

17. The fixed point at which a lever pivots is called a___