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Homework Help: Gravity equation

  1. Mar 16, 2010 #1
    1. The problem statement, all variables and given/known data

    Prob. 3. A block of mass M = 20.0 kg is pushed up a rough inclined plane 37o to the horizontal by a constant force F parallel to the incline as shown. The co-efficient of kinetic friction between the block and the incline is µ = 0.25, and the block is moving up with a constant speed of 2.5 m/s between A and B.

    2. Relevant equations

    3. The attempt at a solution

    What is the magnitude of F ?
    F = 0.25*200cos37 + 200sin37 = 160N
    Can you explain the 200sin37 part. Is that gravity can you break it apart
    gravitational force ? Wg = - 20*200sin37 = - 2400J :
    i thought it would be 20*10*20sin37
    is gravity force g*m*d where d is the hypotenuse or is the vertical side of the right triangle?

  2. jcsd
  3. Mar 16, 2010 #2


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    Homework Helper

    You're thinking about gravitational potential energy. 200sin37 is the component of gravity parallel to the ramp.
  4. Mar 16, 2010 #3
    what about the gravitation force?
    - 20*200sin37

    is that parallel to the ramp as well?
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