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Homework Help: Work required for truck up a hill problem

  1. Jan 29, 2009 #1
    1. The problem statement, all variables and given/known data

    "Is more work required to bring a fully loaded truck up to a given speed than the same truck lightly loaded? Defend your answer"

    2. Relevant equations

    I put:
    Work = Force x distance
    Distance = speed x time
    As speed in a common factor, we take it out
    Work = Force x time.................Is this correct so far?

    So the work is the same.
    Small force, long time, or short time, big force.


    But doesn't work = change in KE?
    so W = 1/2 m x v^2
    ...So the greater one does require more work?

    I don't know...

    Help me please!


    3. The attempt at a solution
     
  2. jcsd
  3. Jan 29, 2009 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Re: Work

    No, not correct. (If work = force*distance, which it does, how can it also equal force*time? The units won't even make sense. FYI: force*time = change in momentum, not work.)

    No.

    Yes!
    Yes!
     
  4. Jan 29, 2009 #3
    Re: Work

    Brilliant, thank you
    =]
     
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