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Homework Help: Finding Normal Force?

  1. Nov 30, 2011 #1
    1. A cup and saucer rest on a table top. The cup has mass of 0.176 kg and the saucer 0.165 kg. Calculate the magnitude of the normal force a). the saucer exerts on the cup and b). the table exerts on the saucer.

    Too be honest I really don't know the equation. I think it might be ΣF=m*a but I'm not sure. And if that is the formula, I do not know how to proceed.
  2. jcsd
  3. Nov 30, 2011 #2
    Start with a free body diagram. The saucer and cup are not moving upwards or downwards, so Fn=Fg.
  4. Dec 1, 2011 #3
    I still don't understand how to find part b. Part a was 1.7 N ([itex]\SigmaF=0.176(9.8)[/itex]
    So I got part a down, but I can't figure out how to do part b. I tried finding the force due to gravity, and then did Normal force-force due to gravity = ma. That didn't work.
  5. Dec 1, 2011 #4
    Never mind, I figured it out!
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