| A | B |
|---|
| Work | Force in the direction of motion. |
| Carrying a box from here to Dallas. Lots of scientific work or no work? | No work. |
| Power | Rate of doing work. Rate of transfering energy to work. |
| Watt | Unit of power. |
| Joule | Unit of energy or work. |
| Effort force | Force you exert. |
| Resistance force | Force exerted by the machine. Often equal to the weight being lifted. |
| Mechanical advantage | Fr/Fe How much easier it is to lift. |
| Efficiency | Wo/Wi X 100% Ratio of work output to work input. Less than 100 % due to friction. |
| Compound machine | Two or more simple machines working together. |
| 1st class lever | fulcrum in the middle. |
| 2nd class lever | load in the middle. |
| 3rd class lever | effort in the middle. |
| 6 Simple machines | screw wedge inclined-plane lever pulley wheel&axel |
| Machines of the inclined plane category | wedge screw inclined-plane. |
| Machines of the lever category | lever pulley wheel&axel. |
| Ideal mechanical advantage | de/dr. |
| Machines | make work easier whether powered by humans or machines. |
