1. Machine notes
CP Physics
Ms. Morrison

2. Machines Devices that make work easier to do (transfer energy)
Two ways make work easier:
Machines change the direction of your force. (ex. Pulleys)
Machines multiply the force you apply to it.
Note: You do the work on the machine and then the machine does work on the object.

3. Simple Machines Six Simple Machines Levers Pulleys Wheel and axles
Inclined Planes
Wedges
Screws

4. Levers Long rigid bar with a support called a fulcrum
Examples: crowbars, car jacks

5. Pulleys Special type of lever
Has grooved wheel over which a rope passes
Can have a single pulley or combinations of pulleys
Examples: window shade pulls, block and tackle, well, flag poles

6. Wheel and axle Special type of lever
Consists of a wheel attached to an axle
Examples: pencil sharpener, egg beater

7. Inclined plane Flat surface with one end higher than the other
Examples: moving ramps, wheelchair ramps

8. Wedge Inclined plane with either one or two sloping sides
Examples: door stops, knives, axes, scissors, chisels

9. Screw
An inclined plane which is spiral, you move the plane rather than the load
Examples: wood screws

10. Mechanical advantage
Indicates how much the machine multiplies your force
Equation: MA = Fr/Fe
MA = mechanical advantage (no unit)
Fr = resistance force (equals weight of the object)
Fe = effort force (force you apply to the machine)

11. Ideal mechanical advantage
Second form of mechanical advantage
Based on an ideal machine which transfers 100% of your energy
Equation: IMA = de/dr
IMA = ideal mechanical advantage
de = effort distance (distance you apply force)
dr = resistance distance (distance machines moves)

12. Efficiency
Shows how much of the work you put into the machine (input work) is actually used to do work on the object by the machine (output work)
Equation: Efficiency = Wo/Wi x 100%
Wo = output work (J)
Wi = input work (J)
Machines cannot multiply your work or energy – they can only multiply force
MACHINES CANNOT DO MORE WORK THAN THE WORK YOU PUT INTO THEM