1. Work Chapter 15 Section 4

2. Objectives Identify 6 simple machines Explain how the machine work Explain the difference between classes of levers Describe how pulleys work

3. Simple Machines An instrument that makes machines work easier Simple machines are divided into two categories Lever family Inclined Plane family

4. Lever Family Simple Lever

5. Lever Family Pulley

6. Lever Family Wheel and Axle

7. Levers All levers have a rigid arm that Pivots or turns around this point. This point is called the fulcrum There are three classes of levers: first class, second class and third class. Levers are placed in these categories by the input, output and where the fulcrum is located.

8. Levers First Class: Hammer taking out a nail The MA depends on where the fulcrum is located. The fulcrum is between the input and output force Second Class: Wheelbarrow The output force is between the fulcrum and the input force. These levers multiply force, so MA is greater than 1 Third Class: Forearm of a person These levers multiply distance, so the MA is less than 1. The input is located between the fulcrum and the output force.

9. Levers

10. Pulley Two types: Fixed pulley and moveable pulley Fixed Pulley: Has a MA of 1 which means it just changes the direction of the force. Movable pulley: has a MA of greater than 1. You can combine fixed and moveable pulley to have a great MA

11. Pulley

12. Wheel and Axle Made of lever and pulley connected to an axle. When a small input turns the wheel, the output is multiplied. This is because the axle is smaller than the wheel, so less distance is covered.

13. Wheel and Axle