- #1
sonoftunk
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Homework Statement
Mass of 22kg on a 45o to the horizontal.
[tex]\mu[/tex]s = 0.78
[tex]\mu[/tex]k = 0.65
Determine the magnitude of the largest force that can be applied upward parallel to the ramp to have the box remain at rest.
AND
Determine the magnitude of the smallest force applied to the top of the box, perpendicular to the ramp, to have the box remain at rest.
Homework Equations
All kinematic-based equations
Newton's Laws
FF = [tex]\mu[/tex]FN
The Attempt at a Solution
I assumed that the magnitude of the maximum force required would be equal to |FNET| + |FF| I got 2.0 x 102 Newtons of force (correct to two significant digits).
However, the second part, I'm not quite sure of what to do. I thought that if you are applying a force perpendicular to the ramp, you would be increasing the force of gravity perpendicular to the ramp, and since |FN| = |FgN| the normal force would increase. Then I thought the absolute value of the force of friction would have to equal the absolute value of the force of gravity acting parallel to the ramp. In that case, just solve to find the force needed.
I was told I was wrong.
(*side note* I didn't find a use for the kinetic coefficient of friction. I assume that it will be useful, but can't think of how)