Physical Science / Unit 8: Work, Energy and Machines
8.3 Simple Machines
Notes
A machine makes work easier by changing the size or direction of a force (it does not reduce the work).
- Six simple machines: lever, pulley, wheel and axle, inclined plane, wedge, screw.
- A lever has a fulcrum (pivot). A wedge is two inclined planes, and a screw is an inclined plane wrapped around a rod.
- A compound machine combines two or more simple machines (scissors, bicycle).
- A machine trades force for distance: less force over more distance.
Practice
Which is an example of an inclined plane?
A ramp is a sloping surface used to lift loads.
What does a machine always do?
Machines make work easier but cannot create energy.
A pair of scissors is best described as:
The handles are levers and the blades are wedges.
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