Give me a grip and move the world

2001/04/01 Ares, Felix Iturria: Elhuyar aldizkaria

• Fisika

The Ptolomeo boat hit the bottom of the beach and it was impossible to move. There were twenty people who pushed, but without a doubt. The boat did not move. Archimedes went through there and offered to collaborate. To see Ptolemy and that yes, he needed help, but that two hundred scholars like him could do nothing, Archimedes called the captain and asked him to take the trunk of a tree under the ship. Then, Archimedes heads to the other end of the trunk and pushes it down. The boat got up to everyone's surprise.

Ptolemy thanked Archimedes and was able to leave to the sea. The explanation is very simple. The trunk and the stone form the so-called lever. That is, a simple “machine” that serves to amplify the force. The principle of lever was discovered by Archimedes.

You can check the amplification power yourself. Take three or four books and put them on top of each other. Try to get up with your little finger, the least strong. You will see how you can't or will cost you a lot in the best.

Now we put a pencil under the books (see photo 1). Place a second pencil under the first as close as possible to the books (see photo 2). With the small finger you will push the pencil to the end (see photo 3) and you will see that now the books will lift them without any difficulty.

Archimedes found the mathematical formula to explain what happens. But without using these formulas you can see that the finger travel down is longer than the book travel up. There is the key, because the relationship is between distance and force. In other words, the strength you must make to lift the books is smaller if you use the lever, on the contrary, the finger path will be longer.