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Homework Help: Simple Force Problem

  1. Oct 4, 2005 #1
    I'm working on the current problem:

    A woman stands on a scale in a moving elevator. Her mass is 65.0 kg, and the combined mass of the elevator and scale is an additional 815 kg. Starting from rest, the elevator accelerates upward. During the acceleration, the hoisting cable applies a force of 9450 N. What does the scale read during the acceleration?

    I figured out that the woman exerts a force of 637N. I also figured out that the scale and elevator exert a downward force of 7987 N. I added both of those forces and then tried finding the difference between the upward motion of 9450 N and 8624 N. That was incorrect.

    I then tried using the formula apparent weight = mg + ma. I figured if I could calculate the acceleration for that equation I would derive the apparent weight the scale was reading. However, using the sum of the forces in the Y direction (subtracting 9450 N from 8624 N) and dividing that with 65.0 kg gets me basically the same answer as before. Any help would be appreciated.
  2. jcsd
  3. Oct 4, 2005 #2
    You can find a in your apparent weight equation using the total mass of the system (880 kg) and the upward force (9450 N)

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