4. Simple Machines Machines do not save work. Machines make work easier. Machines make work easier because it changes either the size or the direction of the force put into the machine.

5. Work Input vs. Work Output The work you do on a machine is called work input. The work done by the machine is called work output.

6. Mechanical Advantage A machine’s mechanical advantage tells you how many times a machine multiplies force. Mechanical Advantage = Output Force Input Force

7. Simple Machines There are 6 types of simple machines: –Levers –Inclined plane –Wedge –Screw –Pulley –Wheel and axle

8. Levers A lever is a simple machine consisting of a bar that pivots at a fixed point. The fulcrum is the fixed point. There are 3 classes of levers depending on the location of the fulcrum, the load, and the force.

9. First Class Levers With a first class lever, the fulcrum is between the input force and the load. Examples of a first class lever are a seesaw, scale and pliers. Load

10. Second Class Lever A second class lever has the load between the fulcrum and input force. Examples of a second class lever are wheelbarrow, door, and bottle opener. Load

11. Third Class Levers A third class lever has the input force between the fulcrum and the load. Examples of a third class lever are tweezers and shovels. Load

12. Inclined Plane An inclined plane is a simple machine that is a straight, slanted surface like a ramp. An inclined plane increases the distance but decreases the force that is applied.

13. Wedge A wedge is a double inclined plane that moves. Examples of wedges are knives, axes, and zippers.

14. Screws A screw is an inclined plane that is wrapped around a cylinder. Examples are jar lids, bottle caps, bolts, and screws.

15. Pulleys A pulley is a rope, belt, or chain wrapped around a grooved wheel. The more wheels a pulley has, the less input force required. Examples of pulleys are a crane and flag pole. Which is easier to use- a pulley with one wheel or a pulley with 3 wheels?

16. Wheel and Axle A wheel and axle is a simple machine consisting of two circular objects of different sizes. The axle is the smaller of the two circular objects. Examples of wheel and axles are doorknobs, wrenches, Ferris wheels, and steering wheels.

17. What type of simple machine is Zero’s shovel? Label the input force, output force, load, and fulcrum on Zero’s shovel.