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Study Guide - 3.2 Force, Motion, and Energy
Simple Machines are tools that make work easier. Work made easier might include
lifting heavy weight, moving heavy objects over a distance, pushing things apart,
changing the direction of a force or holding an object together.
The six simple machines are the lever, inclined plane, wedge, wheel and axle,
screw, and pulley.
1. Lever – lifts – stiff bar, rests on fulcrum
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The closer the fulcrum is to the load the easier it is to lift.
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A lever is a simple machine made of a stiff bar that moves about a fixed
point (fulcrum) – helps us do work more easily.
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A lever is a simple machine that is used to push, pull, or lift things.
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A force of effort is applied to one end of the bar or rod to lift a load at the
other end.
2. Inclined Plane – low on one end, high on other; makes it easy to go from low to
high or high to low place
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The inclined plane is a flat surface that is raised so one end is higher than
the other.
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The inclined plane helps heavy objects move up or down.
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An example of an inclined plane is a ramp, steps, escalator, etc.
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Moving a load up the ramp (inclined plane) requires less force than lifting
the load.
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3. Wedge – wide at one end, narrow at other end; splits and cuts
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The wedge is wide at one end and pointed at the other to help cut or split
other objects. Examples include a knife, ax, pin, needles, nails, etc.
4. Wheel and Axle – wheel attached to rod; makes it easier to move or turn things
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The wheel and axle consists of a rod attached to a wheel.
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Examples include: bicycle wheels, roller skates, door knobs, etc.
5. Screw – grooves used to tighten, fasten, loosen
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A common use of the screw is to hold objects together. Examples
include a screw in the desk let, drill, etc.
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6. Pulley – wheel with rope or chain; changes direction or amount of force
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Pulley is a wheel with a rope wrapped around it. Pulleys can be used to
lift heavy object.
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Examples: flagpole, window blinds
Compound Machines – Two or more simple machines combined to do work more
easily
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Magnets
Poles – the two areas of a magnet – North Pole and South Pole
Repel – pushes away from the magnet or from the poles of the magnet
Attract – pulls to itself; magnets pull or attract certain metals;
Natural Magnets – Lodestone is a natural magnet.
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Lodestone is a magnetic type of rock
Artificial Magnets – iron or steel that has been artificially made to have the properties of
a magnet
Magnetic Compass – the magnetized needle in a compass (used for direction) is a
magnet and always points to Earth’s magnetic North Pole; always points
north.
Types of Magnets
Bar Magnet
Horseshoe Magnet
Ring Magnet
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