槓桿的作用 (The uses of lever)

  If you want to find out the uses of lever, the following experiment may be useful.

  First, you need to prepare four books and two pencils.

  What we can do is to pile up the books. Put your last finger below the books and then pile up.

  Then put a pencil under the books, and put another pencil into the bottom of the books and above the pencil. But the two pencils must be formed as an angle of 90 degrees. At last, use your last finger again to pile up the books but this time you only need to press the tip of the pencil.

  The situations are: You will find more difficult  you use your last finger to pile up the books. But when you use the pencils to help you, u will find easier to pile up the books.

Why?

  It is because the pencils form a lever, a pencil is equal to a fulcrum. Another pencil is equal to a force. If your acting force is far away from the fulcrum, you will find easier to pile up something. A lever is to enlarge the power. It make you easier to move or pile up things.

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