1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Food-energy to Mechanical Energy

  1. Dec 18, 2009 #1
    1. The problem statement, all variables and given/known data
    The nominal food-energy value of 1.00g of butter is about 7.20 food calories.

    If all this energy could be converted completely to mechanical energy, how much butter would be required to power a 65.0kg mountaineer on her journey from Lupine Meadows (elevation 2070m) to the summit of Grand Teton (4196m)?

    2. Relevant equations

    3. The attempt at a solution

    What I tried was (65 * 9.81 * 2126) to find the Joules of energy required for the journey. Then converted 7.2 food calories to 30.1248J and divided to find the grams.

    I came out with approx 4.5x10^4g of butter, however it is not being accepted as correct.
    What am i doing wrong?
  2. jcsd
  3. Dec 18, 2009 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Note that food calories are really Kcals = 1000 calories.
  4. Dec 18, 2009 #3
    Yep that solved it...

    Thank you for the correction!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook