Question

How long will the energy in a 1470-kJ (350-kcal) cup of yogurt last in a woman doing work at the rate of 150 W with an efficiency of 20.0%?

a) 7.5 hours
b) 8.5 hours
c) 9.5 hours
d) 10.5 hours

Answer 1

The energy in a cup of yogurt will last for 7.5 hours in a woman doing work at a rate of 150 W with an efficiency of 20.0%.

Step-by-step explanation:

To determine how long the energy in a cup of yogurt will last in a woman doing work, we need to calculate the time using the given information. The power output of the woman is 150 W, and the efficiency is 20.0%. We can calculate the energy output using the formula:

Energy output = power output * time

Using this formula, we can rearrange it to solve for time:

Time = energy input / (power output * efficiency)

Substituting the given values, we get:

Time = 1470 kJ / (150 W * 0.20) = 7.5 hours

Therefore, the energy in the yogurt will last for 7.5 hours.