The lever gives a gain in strength by 2.5 times. find the arms of the lever if its length is 70 cm.

Let’s designate one shoulder as x, then the second shoulder will be 2.5 * x.

x + 2.5 * x = 70;

3.5 * x = 70;

x = 70 / 3.5;

x = 20.

20 * 2.5 = 50.

Check: F1 / F2 = 50/20 = 2.5. The ratio of forces is inversely proportional to the length of the shoulders and is equal to 2.5.

Answer: one shoulder 20 cm, the second shoulder 50 cm.