Question

nent of the progress bar may be uneven because questions can be worth more or less (including zero ) depending on your answer. 5-ounce container of Greek yogurt contains 150 calories. Find the unit rate of calories per ounce.

Answer 1

The energy from a 1470-kJ (350-kcal) cup of yogurt at 20% efficiency will last approximately 32.55 minutes when doing work at 150 W. This implies the ease of consuming more calories than can be burned off through exercise alone.

Step-by-step explanation:

The question involves calculating the duration for which the energy from a 1470-kJ (350-kcal) cup of yogurt will last for a woman doing work at a rate of 150 W assuming a conversion efficiency of 20%. To find out how long the energy will last, we first convert the energy content of the yogurt into joules (since calories are not the standard unit of energy in physics).

1 kilocalorie (kcal) = 4.184 kilojoules (kJ), so 350 kcal equates to 350 * 4.184 kJ = 1464.4 kJ. However, since the body's efficiency is 20%, the usable energy is only 20% of 1464.4 kJ, which is 0.2 * 1464.4 kJ = 292.88 kJ.

The power output (the rate of doing work) is 150 watts (W), where 1 W = 1 joule/second (J/s). To calculate the time (in seconds) the energy will last, we divide the usable energy by the power output: Time (s) = 292.88 kJ / 150 W = 1952.8 seconds, or approximately 32.55 minutes.

Considering part (b), the calculated time suggests that it is quite easy to consume more food energy than can realistically be expended through exercise, highlighting the challenge of relying solely on exercise for weight management.