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Homework Help: Machines Problem

  1. Dec 9, 2007 #1
    [SOLVED] Machines Problem

    1. The problem statement, all variables and given/known data

    A ramp, 18m long and 4.5m high is set up in order to wheel a 25-kg box at a constant speed. Assume that by wheeling it there is no friction.

    2. Relevant equations

    IMA= [tex]\frac{d_{in}}{d_{out}}[/tex]

    3. The attempt at a solution

    I know this is a pretty simple problem but I don't know how to tell which distance is "in"and which is "out".

    Please help, I can't find any sample problems in my book and we never got any practice in class...and I have a test tomorrow! :( Thank you.
  2. jcsd
  3. Dec 9, 2007 #2


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    What are you trying to find out - what is the actual question ?
  4. Dec 9, 2007 #3
    o, im sorry, I have to find the IMA and MA... (ideal mechanical advantage and mechanical advantage).
  5. Dec 9, 2007 #4


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    Ok, I hadn't seen the acronym before.
    Mechanical advantage is generally = distance you apply the force over / distance work is done.
    So in an inclined plane = length of slope / height of slope
    If there is no friction then Ideal MA would = MA

    To work out which way up, you would generally want a MA > 1 so you do less work for a longer distance to move a heavy load a short distance.

    ps. Although not always, high gear on a bike has fractional mechanical advantage so you apply a large force over a small diustance to move the bike wheel a large distance with low force.
    Last edited: Dec 9, 2007
  6. Dec 9, 2007 #5
    ok thanks so much!! :D
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