Burning Calories: Calculating Time to Radiate 285 Calorie Donut

[iseidthat]

Homework Statement

If a person radiates about 67 W of power at room temperature, how long does it take (h) for a person to radiate away the energy acquired by consuming a 285 Calorie donut?

Homework Equations

i know W=J/s
no clue, i need one that involves time.

The Attempt at a Solution

i've tried 285/67=4.25 sec...but that's wrong...
and i don't think the problem is asking in Kcals
help?

 

[Dick]

You need to figure out how many joules there are in 285 calories. And I'll bet they are talking about Kcal's. They almost always are when referring to food.

 

[iseidthat]

ok...
285 Cal=285,000 cal (4.186)= 1.19e6 J

how do i relate it to time though?
do i just divide it by the power?
1.19e6/67=17806 s/60/60=4.95 h
ok thanks

 

[Dick]

Sure. J/(J/sec)=sec.