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Determine the coefficient of kinetic friction

  1. Nov 30, 2012 #1
    1. The problem statement, all variables and given/known data

    A 20.0g object is placed against the free end of a spring (k = 25.0 N/m) that is compressed 10cm. Once released, the object slides 1.25m across the tabletop and eventually lands 1.60m from the edge of the table on the floor. Is there friction between the object and the tabletop? If there is, what is the coefficient of kinetic friction? The sliding distance on the tabletop includes the 10cm compression of the spring, and the tabletop is 1.00m above the floor level.

    2. Relevant equations

    U(x)=(1/2)kx^2
    F=-kx
    W=fd
    f=umg
    F=umgd

    3. The attempt at a solution

    d=(1.6-1.25) = .35m
    U(x) = (1/2)(25)(.35^2)
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Nov 30, 2012 #2

    Simon Bridge

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    Please explain your reasoning.
    How are you thinking about the problem?
    I can see some working - like you have d as the difference between the how far the object slides across the table and how far it flies off the end of the table ... and you appear to think this has something to do with the energy stored in the spring?

    Consider:
    How far was the spring compressed?
    If there were no friction, and no air resistance, where would the object have ended up?

    Is there friction in the system?
     
  4. Nov 30, 2012 #3

    tiny-tim

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    welcome to pf!

    hi woopycushion! welcome to pf! :smile:

    (try using the X2 button just above the Reply box :wink:)

    show us what you've tried, and where you're stuck, and then we'll know how to help! :smile:
     
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