A 2 kg block rests on an inclined plane with an angle of 30. A force of 5 N is applied to the block in a direction down the incline plane until the block begins to move when the force reaches 7.3 N, what is the approximate coefficient of static friction between the block and the plane?
The Attempt at a Solution
I made a FBD, labeled normal, weight (and its x and y components), the Ff, and the Fapplied. I made a force table to lay out all the knowns:
Fn Weight Fapplied Ff
nx=0 W=mg FAX=-7.3N Ff=μn
ny=+n Wx=-10N FAY=0N Ffx=μn
0-10-7.3+μn = 2ax n-17.3 = 2(0)
-17.3 + μsn = 2ax n = 17.3 N
In ΣFx, I have 2 unknowns. How to solve for μs?