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Homework Help: A person pulling a lawn mower

  1. Mar 24, 2012 #1
    1. The problem statement, all variables and given/known data
    A person pulls on a 20kg lawnmower with a force of 25.0N and moves the mower 4.50metes. The handle angle is 15* with the horizontal and μ=0.100.
    a) Work done by person √ = 109J
    B) Work done by friction √ = -85.3J
    C) Find the time ????

    2. Relevant equations
    P= W/T = W*(constant velocity)

    3. The attempt at a solution

    I tried to use one of the power equations though I had 2 unknowns (P and T). I have no idea how to go about finding the time.
  2. jcsd
  3. Mar 24, 2012 #2


    User Avatar

    Staff: Mentor

    What's the net horizontal force on the lawnmower? What then is the motion? Can you think of a suitable kinematic equation to find the time given the distance traveled?
  4. Mar 24, 2012 #3
    Thank you very much for the help :D. Got it 5.89s
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