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Work and Energy: Spring

  1. Feb 12, 2009 #1
    Ladle Attached to Spring A 0.23 kg ladle sliding on a horizontal frictionless surface is attached to one end of a horizontal spring (with k = 490 N/m) whose other end is fixed. The mass has a kinetic energy of 10 J as it passes through its equilibrium position (the point at which the spring force is zero).

    (a) At what rate is the spring doing work on the ladle as the ladle passes through its equilibrium position?

    i got this correct: 0 watts

    (b) At what rate is the spring doing work on the ladle when the spring is compressed 0.10 m and the ladle is moving away from the equilibrium position?
  2. jcsd
  3. Feb 12, 2009 #2
    First you must find the force in the spring at x=.1m which can be found through the equation F=kx. Therefore, the force will be 49N. Then you know that WORK=FORCE*DISTANCE. Therefore W=(49N)*(.1m)=4.9J. This should be correct, though it might be negative.
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