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Homework Help: Frictionless incline problem

  1. Nov 28, 2012 #1
    1. a block B is placed on an inclined plane T ( a right triangle). the triangle rests on a flat surface. zero friction is assumed. what is the acceleration of T & B?

    2. no angle of the triangle is given so i just added in θ on intuition. my best guess is something along the lines of:

    3. acceleration of T = B/T * Gravity * sin(θ)

    acceleration of B = T/B * Gravity * sin(θ)

    thanks for the help
  2. jcsd
  3. Nov 28, 2012 #2
    It is a nice question.I am getting that acceleration of the T is (B/T)gtanθ
    and on the block is gsinθ.Just draw free body diagram.and now see forces acting on the incline(Do not forget that normal reaction due to block)find it and equate Fnet=ma.and done
    and second one acceleration is it is moving due to mgsinθ force so find it acceleartion.
  4. Nov 28, 2012 #3


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    This is quite a tricky problem because the direction of acceleration of the block is not obvious. Its acceleration relative to the triangle will be down the incline, but its acceleration relative to the flat surface will not be.
    Set the normal force between the block and triangle to be N and write down the free body equations for each mass.
  5. Nov 28, 2012 #4
    Yeah i forgot that thing.
  6. Nov 29, 2012 #5
    FBD for both

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    Last edited: Nov 29, 2012
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