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Simple Machines: Lifting with Levers

Everyday Einstein looks at levers, how they work, and how to classify them.

By
Lee Falin, PhD,
April 26, 2013
Episode #052

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In an earlier episode on pulleys, we introduced the idea of simple machines acting as force multipliers. We also talked about how pulleys work, and how they allow you to lift things you normally wouldn’t be able to lift. However pulleys aren’t the only type of simple machine, and today we’re going to discuss the second machine on our list: the lever.

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Eureka!

Some people say that Archimedes once said something like “Give me a stick and a place to stand, and I shall move the world.” If he really did say this, it was with good reason, because it is thanks to Archimedes that we understand the law of the lever.

There are 3 types of levers, conveniently enough called “class 1 levers,” “class 2 levers,” and (you guessed it), “class 3 levers.” What kind of class the lever belongs to depends upon the relative location of 3 things:

Thing #1: The force you apply to the lever (sometimes called the effort)

Thing #2: The thing the lever is supposed to move (sometimes called the load)

Thing #3: The part that the lever balances on (usually called the fulcrum).

Let’s take a look at how you would use these different classes of levers.

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