Stair Climbing- Arthur La Porta - PHYS171 - November 2011 In the third midterm I asked how much work your body does when climbing a flight of stairs, and when walking up the down escalator, climbing at constant velocity so that you remain in place as the stairs move below you. In retrospect, I think the phrasing of the question can lead to confusion, since it requires you to imagine the work your body does on itself, which is not entirely clear. I think it is more clear to pose the question in a slightly different way. Assume you are carrying a box of mass m , and that your own mass is negligible compared with the mass of the box. (You can think of the box as a surrogate for your own mass.) How much work do you do climbing a flight of stairs with the box, or climbing an equal number of stairs, but climbing up the down escalator and remaining in place. First consider the forces involved. If you are moving at constant velocity (no acceleration) you exert force + mg on the box to keep it from falling, and you exert force
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This note was uploaded on 12/29/2011 for the course PHYSICS 171 taught by Professor La porta during the Fall '11 term at Maryland.