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How well will my couch be rumbled?

  1. Dec 24, 2003 #1
    I have this thing, given about 25 watts, it'll provide a force of 10 Lbf (44.5 N) This thing has a mass of ~2.5 pounds. I'll mount it to a couch with a mass of about 200 pounds (with a person on it)

    What'll happen?

    If I had a ball that was the same mass, and threw it at the couch, how fast would the ball be traveling to produce the same force?


    If you need any more info just ask.
  2. jcsd
  3. Dec 24, 2003 #2
    A device which has a mass of 2.5 pounds and produces a force of 10 lbs can only indent the couch with the force of 2.5 pounds. If the device had the same mass and produced a force of 1 million pounds, the couch would still be indented by 2.5 pounds.
    Think of a hydraulic jack with it's rear end resting on the couch.

    How fast should the 2.5 lb ball thrown at the couch be traveling to achieve the same indentation effect? Zero speed. Just rest it on the couch.
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