A box with a mass of 22 kg is at rest on a ramp inclined at 45 degrees to the horizontal. The coefficients of friction between the box and the ramp are uS = 0.78 and uK = 0.65.
a) Determine the magnitude of the largest force that can be applied upward, parallel to the ramp, if the box is to remain at rest.
b) Determine the magnitude of the smallest force that can be applied onto the top of the box, perpendicular to the ramp, if the box is to remain at rest.
Fg = mg
Ff = ukFn
Ff = usFn
The Attempt at a Solution
I dont know where i should begin, i understand thati need to find the force of friction using static friction but I'm not sure how to start it.