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posted by  jazbo.fe on 7/22/2009 6:02:04 PM  |  status: Closed  |  Earned Karma: 25

Application of Newton's Laws

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A backpack full of books weighing 52.0 N rests on a table in a physics classroom. A spring with a force constant of 130 N/m is attached to the backpack and pulled horizontally.
         (a) If the spring is pulled until it stretches 2.00 cm and the pack remains at rest, what is the force of friction exerted on the backpack by the table?            N.
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Sage
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posted by MasterChef on 7/22/2009 6:05:04 PM  |  status: Live
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There are two forces acting on the backpack. The spring force in one direction and the force of static friction in the other direction. Since the object is not in motion, these two forces must be equal, so we have:
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Oracle
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posted by VSL on 7/22/2009 6:06:56 PM  |  status: Live
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"In physics, you don't have to go around making trouble for yourself - nature does it for you" - Frank Wilczek
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