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Homework Help: Forces - Elevator 2 part question

  1. Oct 22, 2007 #1
    Hi I just needed help with a question with 2 parts. I just need to know where to start and what formula is recommended for use.

    For example:
    Larry is standing on a scale in an elevator, the scale reads x. The elevator accelerates upwards at x m/s/s. The elevator weighs xx. How much does the scale read now?

    Also same thing but acceleration is downwards.

    Thanx for the help :D
  2. jcsd
  3. Oct 22, 2007 #2
    Do you have any formulae at all?
    Do you understand the concept of what is happening when the elevator is moving?
  4. Oct 22, 2007 #3
    the formulas that need to be used are w=mg, f=ma
    and something about Sigma F
  5. Oct 22, 2007 #4
    You need to sum your forces before and during the elevator movement. You know what weight is, mg. You know that before the movement there should only be 2 forces and they balance out. Now you need a free body diagram for the movement. You know that the elevator is moving upwards so sum your forces again and try from there.
  6. Oct 22, 2007 #5
    when you say sum your forces, you mean like upwards is positive and downwards is negative so it would be Fn-W right?
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