1. Remember average speed? You should. Avg. Speed = Distance (m) / Time (sec)
2. Friction is the force that opposes motion and transforms work into heat. Friction can be decreased by adding things like oil or water onto two surfaces that are rubbing together. Friction can be increased by adding things like sand or grit between two surfaces.
3. Know the three classes of levers:
1st Class— Fulcrum in the middle
2nd Class—Load is in the middle
3rd Class— Effort is in the middle
4. Work happens when an object is moved a distance by a force. If two forces are going the same direction they add together. If they are going opposite directions they will subtract from each other.
5. Machines make work easier.
6. Efficiency compares the output of a machine to the input: Efficiency = output work / input work x 100%
7. Power = work (j) / time (s)
8. Inclined planes (ramps) that are longer have more Mechanical Advantage.
9. You might also want to review the concepts of kinetic and potential energy and the law of conservation of energy from Unit 5.
