Burning Calories: Calculating Time to Radiate 285 Calorie Donut

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To calculate the time required for a person radiating 67 watts to dissipate the energy from a 285 Calorie donut, first convert calories to joules, resulting in approximately 1.19 million joules. The formula to find time is to divide the total energy by the power output. Thus, dividing 1.19 million joules by 67 watts gives about 17,806 seconds, which converts to approximately 4.95 hours. This calculation confirms that the problem is indeed referring to kilocalories, commonly used in food energy. Understanding the relationship between energy, power, and time is essential for solving similar problems.
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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?
 
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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.
 
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
 
Sure. J/(J/sec)=sec.
 

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