At room temperature, a typical person loses energy to the surroundings at the rate of 62 W. If this energy loss has to be made up by an equivalent food intake, how many kilocalories (food calories)
Does this person need to consume every day just to make up this heat loss? (1 cal = 4.186 J)
A) 1500 kcal
B) 1300 kcal
C) 1600 kcal
D) 1100 kcal
E) 1000 kcal

Question

Quizplus · Accepted Answer

First, convert the energy loss rate from watts to joules per day: $62 \, \text{W} = 62 \, \text{J/s}$. There are $86400 \, \text{s}$ in a day, so the daily energy loss is $62 \, \text{J/s} \times 86400 \, \text{s/day} = 5356800 \, \text{J/day}$. To convert joules to calories, divide by $4.186 \, \text{J/cal}$: $5356800 \, \text{J} / 4.186 \, \text{J/cal} = 1280400 \, \text{cal}$. Since $1 \, \text{kcal} = 1000 \, \text{cal}$, the daily energy loss in kcal is $1280400 \, \text{cal} / 1000 = 1280 \, \text{kcal}$. The closest answer is 1300 kcal.

At Room Temperature, a Typical Person Loses Energy to the Surroundings