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Homework Help: Solving for applied force to push an object up a ramp.

  1. Jun 17, 2010 #1
    A box, mass 100kg, must be pushed onto a table using an inclined plane 1.5 m high. The plane is 4 m long. If the pleane offers a frictional force equivalent to 10% the weight of the box, what force must be applied to move the box?


    What I tried:
    sin^-1(4/1.5) = 22.6
    100 * 9.8 = 980 N (fgrav)
    980cos22.6=904.77N (Fperpendicular)
    Ffrict=10%980=98N


    That's where I get stuck. I'm not sure if I'm even doing it right (However, I know the angle is).

    Please help. My exam is tomorrow.
     
  2. jcsd
  3. Jun 17, 2010 #2
    angle (theta)=sin^-1(1.5/4)=22.02 deg. (You take sin^-1 (4/1.5))

    Use summation F(x)=0
    friction and mg sin (theta) direction is downward . Applied force dirction is upward.Yes your friction is 98 N. No need to consider Y direction here.
     
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