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potential energy

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Question:

b) You jump as high as you can. Estimate how much energy you have spent. A diet for an average person is 2000kcal per day. knowing that 1kcal=4.2kj- how many jumps should an average person make in order to spend the energy he/she consumed (disregard the energy needed to breath, heat the body, etc. but you can estimate this too and play with numbers.

Answers:

LAPHROAIG

Oracle

Karma Points: 13,361

(Santa Fe Community College-New Mexico)

Date Posted: 6/16/2008 11:59:26 AM Status: Live

Asker's Rating: Lifesaver

Response:

a) If we say that you weigh 65kg and each floor is approximately 2 meters high, then we would have to travel 22meters (2(11)), so the gravitational potential energy would just be PE=mgh=(65kg)(22m)(9.8m/s²)= 14014 Joules
b)We will say that we weigh 65kgs and can jump to a max height of about half a meter, so the energy that we would use would be about PE=(65)(.5)(9.8)=318.5 Joules/ Jump. Now we need to convert to kcal, so .3185kj(1kcal/4.2kj)= .0758 kcal. So the amount of jumps needed would be approximately 2000/.3185= 6279 jumps in a day.

Tope07's Comment:

thanks

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potential energy

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