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Ch. 12 Work Review
Term | Definition |
---|---|
Work | Force times distance. Measured in Joules (J). |
Power | How quickly work gets done. Measured in Watts (W) |
Horsepower | Measure of the power output for car engines. |
Machine | Makes work easier. |
How Machines Make Work Easier | Change force, distance, or direction of effort force. |
Input Force | The force you put into the machine; sometimes called the effort force. |
Output Force | The force that comes out of the machine. |
Mechanical Advantage | A number that tells you how much easier a machine makes your work. Has no units. |
Inclined Plane | A flat, slanted surface. Stairs or a ramp are examples. |
Wedge | Tapers to a thin edge. Used for cutting. An axe or a knife are examples. |
Screw | An inclined plane wrapped around a cylinder. |
Lever | A rigid bar that rotates around fixed point (fulcrum). A door and a crowbar are examples. |
Wheel and Axle | Two cylinders connected by a common axis. |
Pulley | A grooved wheel with a rope around it. |
Fulcrum | The fixed point that a lever rotates around. |
Compound Machine | Made of two or more simple machines. A bicycle and a wheelbarrow are examples. |
Efficiency | Tells you how good a machine is at converting input work into output work. Expressed as a percentage. |
Friction | Reduces the efficiency of machines. |