What is a machine?
How many machines have you used today? Why did you use them? A machine is a device that makes work easier. A can opener like the one in Figure 16 is a machine that changes a small force applied by your hand into a larger force that makes it easier to open the can. A simple machine is a machine that uses only one movement. A screwdriver is an example of a simple machine. It requires only one motion—turning. Simple machines include the pulley, lever, wheel and axle, inclined plane, wedge, and screw. A compound machine is a combination of simple machines. The can opener is a compound machine that combines several simple machines. Machines can make work easier in two ways. They can change the size of the force you apply. They also can change the direction of the force.
LEVERS
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Using an Inclined Plane
