1. The problem statement, all variables and given/known data At a construction site, a small crane is raising two boxes of nails on a plank to the roof. One box has already been opened and is half full, while the other box is new. The boxes, including the nails weigh 10kg and 20kg, respectively, and are the same size. If the coefficient of static friction is 0.4, draw an FBD for each box of nails and use it to calculate the angle at which each box begins to slide. Given: m1=20kg, m2=10kg, μ=0.4 Required: Ffm1, Ffm2 2. Relevant equations Fg=mg FNet=ma Ff=μFN 3. The attempt at a solution Let the directions below equal positive: M1: FNety=Fgy-FN 0 = Fgy-FN Fgy=FN (mg)cosθ=FN (20kg)(9.8N/kg)cosθ=FN FN=196cosθ FNetx=196sinθ-μFN =196sinθ-(0.4)196cosθ =196sinθ-78.4cosθ This is where I'm at currently and Im not sure what to do as it doesnt seem like there's any way to solve for theta due to multiple variables....Is there an important step I'm missing?