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Levers and Pulleys |
A machine is a tool that makes work easier to do. Simple machines are machines with few or no moving parts. A lever is an example of a simple machine. It is a straight bar that moves on a fixed point. The load, fulcrum, and force are parts of the lever. Levers can change the amount of force needed to move something and allows you to change the direction of the force.
A wheel and axle is another example of a lever. This is a simple machine that turns on a post. The post is called the axle. The wheel and axle makes work easier by changing the strength of the turning force. Car steering wheels, car wheels, windmills, and water faucets are examples of wheel and axle machines. A windlass is a simple machine used to raise water from a well.
A pulley is another kind of lever which uses a wheel and a rope to lift a load. There are two different kinds of pulleys. For the one-wheel pulley, both force and load are equal. For the two-wheel pulley, the load and force are different. For both kinds of pulleys, you have to pull down to lift up.
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