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Homework Help: Inclined Plane

  1. Aug 20, 2006 #1

    danago

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    Gold Member

    Hey. Ive been given this problem:

    "An person wishes to push a box up a hill, inclined at 30 degrees. He is able to push with a force of 450N. If the box has a mass of 20kg, and a force of friction with magnitude 20N applies, what is the acceleration of the box?"

    I drew a diagram, and came up with this:
    http://img135.imageshack.us/img135/1124/incplaneob0.gif [Broken]

    What i did was resolve all of the forces into their components (parallel and perpendicular to the slope), including the weight and normal force, and then add them all.

    I got an answer of 16.6 [tex]ms^-2[/tex], but apparently the answer is 1.9 [tex]ms^-2[/tex]. Would someone be able to maybe quickly work it out, and tell me what the real answer is?

    Thanks very much,
    Dan.
     
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Aug 20, 2006 #2

    Päällikkö

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    Homework Helper

    (450-20-20*9.81*sin(30))/20 = 16.595, so you should be correct. The box should have an acceleration plenty over 1.9 m/s2 even if the hill was vertical.
     
  4. Aug 20, 2006 #3

    danago

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    Gold Member

    ok thanks for confirming that :-)
     
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