First I calculated the forces that were working against mass B.
m(A)g sin 30 + μm(A)g cos 30 = 12.86 N
The force working with mass B is
m(B)g = 9.8m(B)
I thought I could solve for B using F=ma where 12.86 N = (2kg+m(B))*(0.58), but of course, 12.86 N is just the force required to make the...