By using a pulley system, a farmer makes it easier to lift bales of hay by reducing the force needed. The energy she uses to complete the task is 10,000 joules, and the work done on the bales of hay is 8,000 joules. What was her efficiency in this task? (1 point)

Question

Responses

18,000 joules
18,000 joules

80%
80%

125%
125%

2,000 joules

Answer 1

To calculate the efficiency of the farmer's task using the formula for efficiency:

$$\text{Efficiency}=\left(\frac{\text{Useful Work Output}}{\text{Total Energy Input}}\right)\times 100$$

In this case, the useful work output is 8,000 joules (the work done on the bales of hay), and the total energy input is 10,000 joules (the energy she uses).

Substituting the values into the formula:

$$\text{Efficiency}=\left(\frac{8,000,\text{joules}}{10,000,\text{joules}}\right)\times 100=0.8\times 100=80$$

So, the efficiency of the task is 80%.