Question

You swing a hammer, doing 40 J of work. The hammer then hits a nail with 30 J of work. What is the efficiency of the hammer?

A) 50%
B) 75%
C) 100%
D) 125%

Answer 1

The efficiency of the hammer is 75%, calculated by dividing the useful work output (30 J) by the total work input (40 J) and then multiplying by 100.

Step-by-step explanation:

The efficiency of the hammer can be calculated using the formula: Efficiency (E) = (Useful work output / Total work input) × 100. Given that the hammer does 40 J of work (total work input) and then hits a nail doing 30 J of work (useful work output), we can calculate the efficiency as follows:

E = (30 J / 40 J) × 100 = 75%

Therefore, the correct answer is B) 75%. This means that 75% of the energy put into swinging the hammer is transferred to the nail, while the rest is likely lost to other forms such as heat, sound, and deformation of materials.