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Homework Help: How to stop a free-falling elevator

  1. Nov 15, 2006 #1
    This is a different take on an elevator problem:

    An elevator and contents have a mass of 300kg and travels at 2.5 m/s during normal operation. The elevator's cables break and begins to free-fall.

    You need to stop the elevator and the max allowed deceleration is 4m/s^2. There is 0.05m between each side of the elevator and the walls, and the coefficient between steel members and the elevator shaft is mu(k)=0.3.

    I assume that you can use steel wedges to help stop the elevator and then couple it with a spring mechanism at the bottom. But, it seems that even with 4 steel wedges on each side, the spring will need to create a force of ~500N.

    Any suggestions...because I'm kinda all out of ideas

  2. jcsd
  3. Nov 15, 2006 #2
    It all depends on "when" you can apply your options. Is it immediately, or some?what? time before you can apply your options.

    I would flood the bottom of the shaft myself. If you can get 10' of water, then you may only have a few broken legs.
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