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Work constant velocity

  1. Jun 14, 2012 #1
    You are pushing a refrigerator across the floor of your kitchen. You exert a horizontal force of
    291N for 7.5s, during which time the refrigerator moves a distance of 2.7m at constant velocity.

    (a) What is the total work (by all forces) done on the refrigerator?

    (b) What is the work done by friction?

    How can I calculate the work done by friction if a mass isn't provided and there is no acceleration obviously since there is a constant velocity?
     
  2. jcsd
  3. Jun 14, 2012 #2

    tiny-tim

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    welcome to pf!

    hi nbroyle1! welcome to pf! :smile:
    that's right, the acceleration is zero and the velocity is constant …

    so use the work energy theorem :wink:
     
  4. Jun 14, 2012 #3
    Thanks, but don't I need the mass for the work energy theorem also?

    Net work=1/2mv(final)^2-1/2mv(initial)^2
     
  5. Jun 14, 2012 #4
    Is the friction force equal to the force applied since it is a constant velocity? or would that just meant that the object isn't moving at all?
     
  6. Jun 14, 2012 #5

    tiny-tim

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

    in this case, 1/2mv(final)2-1/2mv(initial)2 = … ? :smile:
     
  7. Jun 14, 2012 #6
    doesnt it just equal zero since the velocity is the same?
     
  8. Jun 14, 2012 #7

    tiny-tim

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    yes :smile:

    (lots of exam questions are exactly like this)
     
  9. Jun 14, 2012 #8
    Ok awesome thanks!!!
     
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