1. Machines, Mechanical Advantage, and Efficiency

2. Ideal Machines In an ideal machine, work going in is equal to the work going out, this means it has 100% efficiency. We will talk about this more in a moment. Mechanical advantage is the ratio of the output force to the input force. MA = F out/F in How can mechanical advantage be increased?

3. Different Ways to Calculate Mechanical Advantage MA = force out/ force in MA = resistance force/ effort force MA = effort distance/ resistance distance Ideal MA = Length of input arm/length of output arm (for levers) Remember, MA is a RATIO. In math, a ratio is any fraction. Efficiency is (work out/ work in) * 100

4. Ideal machines in the real world Can a machine be completely friction free in the real world? What are some types of simple machines? (There are 6 main types)

5. The 6: Lever: There are 3 classes of levers which will be discussed. Generally, a lever is a bar that is free to pivot at a fixed point. They make work easier. (formula for IMA previously) Pulleys: simple machines that redirect force. (Fixed pulleys can be considered types of levers) Wheel and Axle: IMA = radius wheel/radius axle Inclined Planes: IMA = length of slope/height of slope Screw: inclined plane wrapped in a spiral Wedge: inclined plane with one or two sloping sides to change the direction of input or output force

6. Types of levers: First-class levers: fulcrum between input and output forces. Used for prying things open usually. Ex: Second-class levers: output force located between input force and fulcrum. In other words, lever is used for lifting something. Ex: Third-class levers: input force applied between output force and fulcrum. You typically hit things with these. Ex:

7. Combining one or more simple machines together make a compound machine. Can you name some examples? _ _ _ _ _ _ _ _ _