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Homework Help: Simple forces question

  1. Oct 11, 2005 #1


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    forgot some details to the question but thats ok because i have a general one: a puck is hit with an initial velocity of 5 m/s and comes to a stop some time later. the question is find the friction coefficient of the ice and puck.

    anyways, when making a forces diagram, i know the friction points back but does anything point forward? is there a force pushing it (after its been hit) and if so, how do you find it?

    what i did to solve it was say the net force equals Fpuck - Ffriction = ma

    they gave the mass and i solved for acceleration using regular kinematics but i had to assume Fpuck was 0. is that true? the answer came out correct but i dont know why the Fpuck=0.
  2. jcsd
  3. Oct 11, 2005 #2


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    and boy am i glad i didnt forget the p...
  4. Oct 11, 2005 #3

    Tom Mattson

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    Staff Emeritus
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    So far so good.

    If it isn't being pulled, pushed, attracted by a magnet, etc then there is no force other than friction acting in the direction of motion.

    It is correct, for the reason given above.
  5. Oct 11, 2005 #4


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    excellent. thanks.
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