Question

What is the efficiency of an out-of-condition person who does 2.10 times 10^5 , {J} of useful work while metabolizing 500 , {kcal} of food energy?

A. 15%
B. 20%
C. 25%
D. 30%

Answer 1

The efficiency of a person can be calculated by dividing the useful work done by the energy input and multiplying by 100%. In this case, the efficiency is not provided in the given answer choices.

Step-by-step explanation:

The efficiency of a person is calculated by dividing the useful work done (in this case, 2.10×105 J) by the energy input (in this case, 500 kcal of food energy) and multiplying by 100% to get the efficiency as a percentage.

Efficiency = (Useful work done / Energy input) x 100%

So, in this case, the efficiency is:

Efficiency = (2.10×105 J / 500 kcal) x 100%

Calculating this gives an efficiency of 42%, which is not one of the given answer choices. Therefore, the correct answer is not provided.

Keywords: efficiency, useful work, energy input, percentage