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GPE, KE, and EPE Homework

  1. Nov 27, 2016 #1
    1. The problem statement, all variables and given/known data
    A box of mass 6.2 kg slides 4.8 m down a ramp that is inclined 38 degrees to the horizontal. What is the velocity of the box right before it hits the ground?
    Mass=6.2 Height=dsintheta? V=is what needs to be found theta=38
    2. Relevant equations
    GPE=mgh=mgdsin(theta)
    KE=1/2mv^2
    New equation:
    GPE⋅+KE⋅=GPE
    mgh⋅+1/2mv^2=mgh
    1/2mv^2=mgh-mgh⋅
    mv^2=2(mgh-mgh⋅)
    V^2=2(mgh-mgh⋅)/m
    v=√2(mgh-mgh⋅)/m

    3. The attempt at a solution
    i just want to see if my equations are correct. if it could be factored even more could someone tell me. like the two mgh's i feel like could be changed but im not too sure. I know h is also h=dsin(θ) but would it be the same for the two since it will be different?
     
    Last edited: Nov 27, 2016
  2. jcsd
  3. Nov 27, 2016 #2

    PeroK

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    I'm not sure I understand what you are trying to do. I think you're trying to say something like:

    The box falls a vertical height ##h = d\sin(\theta)## where ##d## is the length of the slope.

    The loss of GPE is, therefore, ...
     
  4. Nov 27, 2016 #3
    I'm sorry that's what I'm trying to say, I just need a little bit of help on this problem
     
  5. Nov 27, 2016 #4

    PeroK

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    Can you do the next step? What is the loss in GPE?
     
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