A load weighing 100 N is located at the end of a short arm of a 16 cm long arm.

A load weighing 100 N is located at the end of a short arm of a 16 cm long arm. To lift this load, a force of 25 N was applied to the long arm of an 80 cm arm. Determine the efficiency of the arm.

Given:

L1 = 16 cm = 0.16 m – short arm length;

L2 = 80 cm = 0.8 m – long arm length;

P = 100 N – weight of the cargo;

F = 25 N – force applied to the long arm to lift the load.

It is required to find the efficiency of the lever.

Efficiency is the ratio of useful work to complete work. First, let’s find a useful job A1:

A1 = P * L1 = 100 * 0.16 = 16 J.

Now we will find the complete work of A2:

A2 = F * L2 = 25 * 0.8 = 20 J.

Let’s calculate the efficiency: A1 / A2 = 16/20 = 0.8 or 80%.

Answer: the efficiency of the lever is 80%