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Force Calculation Problem?

  1. Mar 11, 2014 #1
    1. The problem statement, all variables and given/known data
    A 25kg box of bricks is to be pushed up a ramp and into the back of a pickup truck. The box-ramp system has coefficients of friction (static = 0.6, kinetic = 0.45). If the ramp is placed at 32 degrees with respect to the horizontal, draw a free body diagram to answer the following:

    a)What minimum force must be applied perpendicular to the box and parallel to the ramp to cause it to begin to accelerate up the ramp at 0.5 m/s^2?
    b)What minimum force must be applied perpendicular to the box and parallel to the ramp to cause it to continue to move up the ramp at 0.5 m/s?

    You are travelling at a steady rate of 24 km/hr as you crest the top of a hill. As you move along the road, the crate travels along a semi-circular arc with a 20 meter radius of curvature.

    c)While you are moving across the very top of the hill, what is the magnitude of the normal force from the truck bed on the crate?

    2. Relevant equations

    3. The attempt at a solution

    I was able to draw the diagram, but I am completely unsure how to go about this. I haven't the slightest idea of what equations to use.
  2. jcsd
  3. Mar 11, 2014 #2
    Maybe you could share your free body diagram?

    To simplify the problem I would rotate your frame of reference to be parallel with the ramp i.e. rotate it 32 degrees. Then use Newton's laws of motion in the direction of interest to arrive at the answer i.e. sum up all the forces in the one direction and set it equal to m*a.
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