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Homework Help: Work on an inclinded plane.

  1. Feb 27, 2010 #1
    1. The problem statement, all variables and given/known data
    The block of ice weighs 500N. It is being pushed up an inclined plane with a height of 3m and a hypotenuse of 6m.

    1a. How much force is need to push it to the top?

    1b. How much work is required to push it to the top?

    2. Relevant equations
    W=Fd=deltaKE=deltaGPE

    3. The attempt at a solution
    I have no idea for 1b. because W=Fd, the force is 500N, and d would have to equal 3m to get the 1,500J needed. However, if this is true, and the force is parallel to the motion, why wouldn't you use the hypotenuse instead of the height for the distance?

    1b. GPE at the top = (500N)(3m) = 1,500J
    Thus, W = Fd
    1,500 J = F(6m) = 250N
    Is this correct?

    Thanks!
     
  2. jcsd
  3. Feb 27, 2010 #2

    PhanthomJay

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    Science Advisor
    Homework Helper
    Gold Member

    You are arriving at the corect answer, but I'm not sure if you understand why. First, your relevant equation is incorrect. Look up the work energy theorem and the conservation of total energy principle. Conservation of energy usually works best for finding work when gravity and applied forces (or friction forces) are at play.
     
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