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Homework Help: Crazy problems

  1. Apr 13, 2008 #1
    1. The problem statement, all variables and given/known data
    1) How many floors do you need to walk up to burn the calories in a big mac?
    no variable given, thats it!

    2. Relevant equations

    3. The attempt at a solution
    alright, so by looking things up on the internet, ive found that a big mac is 540 calories.
    -big mac is 2260.44 J

    -using stairs as 8in distance between, and 12in long, its 14.42in distance for each one, 12 steps in a flight, 173.06in= 4.40m per floor

    ive tried a lot of other things, but there is no way im getting the right answer, any help would be MUCH appreciated. thanks!!!
  2. jcsd
  3. Apr 13, 2008 #2


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    The term 'calorie' as used when referring to food is actually a kilocalorie. I.e. 1000 of the calories you are referring to. Correct for that.
  4. Apr 13, 2008 #3
    You cannot expect to calculate anything from so little data. You could use the formula for potential energy, P.E = mgh and set that equal to energy from a big mac, but climbing the stairs requires far more than simply increasing potential energy.
  5. Apr 13, 2008 #4
    dick, thank you for that information, i will re-calculate some things....

    arunbg, i understand that theres so little info. But thats why my physics teacher is well, lets say "not that great." just make sure not to take professor Chen at UNF.....
  6. Apr 13, 2008 #5


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    You can calculate something. You look up as much as you can and guesstimate the rest. You can determine that it's not 10 floors, nor is it a million floors. Questions like this are extremely important and challenging. It doesn't mean your professor is "not great". The skill of being able to estimate something without knowing all the numbers and fitting it into a standard problem template is really valuable.
  7. Apr 13, 2008 #6
    Agreed, I didn't mean "anything" in that sense. From the OP's post, I was getting the impression that he was looking for an exact answer, which is not possible.
  8. Apr 13, 2008 #7
    Dick, i understand the importance of problems like these, and also that it is not politically correct to regard a professor in a certain manner. Unfortunetly, i have spent beyond numerous hours with my study group this sem. dealing with this teacher, and every student feels the same way :(.

    anyways, back to the problem. Through many different approaches, I keep getting answers anywhere from 2 and 249-400 flights, which would seem far too many in order to burn a big mac's worth of calories. Does anyone have any other insight that may help??

    also, this forum is great!! too bad I didn't stumble upon it earlier, although it will help this summer with physics 2 lol
  9. Apr 13, 2008 #8


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    2 floors is way too low. Hundreds of floors seems about right. You'd be surprised how much work it takes to burn off a big mac. Write down the parts you used to make your estimate. Now google around for another answer to see how close you came. One site I found says 1 big mac=about 60 minutes of vigorous stair climbing. How many floors can you climb in 60 minutes, vigorously? There's another estimate question for you. But 249-400 seems about right. Maybe a little high, but it's not crazy.
    Last edited: Apr 13, 2008
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