1. Work, Energy, & Power

2. Work Work (in science) is calculated by multiplying the force by the distance through which the force is applied. W (Joule) = F (Newton) x d (meter) Only the part of the force in the direction of the motion does work.

3. Input vs. Output Work is done by forces on objects Input: Force by you on the machine Output: Force by the machine on object The work output of a simple machine can never exceed the work input!

4. Efficiency If all the input work is converted to work output, then … W I = W O F I x d I = F O x d O This means that the output distance decreases proportionally to the input distance increases.

5. Efficiency The ratio of the work output to the work input. Eff = (W O / W I ) * 100

6. Power The rate at which work is done.

7. Energy Energy is the ability to do work. Energy is also measured in joules.

8. Forms of Energy Chemical Energy –Stored in chemical bonds between atoms Heat Energy –Makes atoms & molecules move faster and farther apart Nuclear Energy –Holds the nucleus of the atom together Mechanical Energy –Energy of objects due to its motion or position Electromagnetic Energy –Attraction & repulsion of charges Batteries, food, fuel Nuclear power plants, cancer therapy Light, electricity River, sound, rolling ball Friction, pot of large hot water

9. Potential Energy Energy that an object has due to its position above the earth (gravitational potential energy). Based on the mass and the height above the earth.

10. Kinetic Energy Energy of motion. Amount of kinetic energy is based on mass and the velocity of an object.

11. Conservation of Energy Energy can never be created nor destroyed, just transformed from one form into another! The total energy never exceeds the starting energy

12. Energy Conversion

15. Fuel Efficiency Gasoline Heat Light Molecules to move faster & farther apart Motion of vehicle Alternator (make electricity) Unused (heat engine) Friction Radio Wipers Battery Lights