Cross tire wrenches, how long easier to use.
According to the principle of physics, the lever is not the longer the more labor-saving, in actual use, we should select the appropriate length, so that it is easy to use.
As we all know, Archimedes once said, "give me a foothold and a lever that is long enough for me to move the earth."." But as he defended the city, he shouted to several soldiers who were moving stones with levers: "don't use that long lever for a short one."." Why is that? The officers and men are shocked. How about using a short lever? Isn't it too much trouble? But the king commanded that Archimedes said, to believe that he had to do it, skeptical, with much more effort than a long lever. The officers and men were baffled and prepared to consult Archimedes later. Unfortunately, as the castle was breached by the enemy, Archimedes was too late to answer the questions of the officers and men and was killed by the Rome soldiers. Now let's help Archimedes with this task.
It turned out that when we study leverage in peacetime, are light lever based, that is, regardless of lever weight, so the longer the lever, it can also be adjusted, so that the greater the power arm, it will be more labor-saving. But when the leverage is taken into account, the situation changes, and we illustrate it through typical data calculations.
