Sean W. answered • 02/04/17
Tutor
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Biomedical Engineer from Vanderbilt
Hi Leann,
Remember that 1 food calories is actually 1 kcal or Cal, which is 1000 calories (cal). 1 calorie is equal to 4.184 Joules (J). Since power is work over time and work is a form of energy in units of Joules, we only need to convert 3000 Cal / day to a certain number of Joules / second, to get Watts.
(3000 Cal / day) * (4184 J / Cal) * (1 day / 24 hours) * (1 hour / 3600 s) ≈ 145.28 J/s (W)
Hope this helps!
Sean W.
Leann, it's all about converting units and figuring out which units are used. Best of luck!
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02/04/17
Ryan D.
Sean , I contacted you on the site here. This exact word problem is out of my Energy & the Environment text. This is the kind of problem I need help with.. Ryan D.
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01/24/19
Ryan D.
Let me ask this. If you're already converting Cal to J, why multiply them together? Aren't they measuring the "same thing?" Or am I missing something?
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01/24/19
Leann B.
02/04/17