1. The problem statement, all variables and given/known data A 10 kg box rests on a horizontal surface. The coefficient of static friction is 0.85. If a force is applied to the object at 30° above the horizontal, what is the minimum magnitude this force must have in order for the box to slide? 2. Relevant equations Fnet = ma Fs = usFn 3. The attempt at a solution m=10kg us=0.85 Theta=30 Okay so Fnet = ma and since the box is at rest, Fnet = 0 The net force is the force we're trying to find minus the friction force making F - Fs = 0, F = Fs Fs is us*Fn which is 0.85*mg which is 0.85*10kg*9.8 which calculates to 83.3N Now here is where I'm stuck, the equation now looks like F = 83.3N, which should be the answer but it isn't since the answer is 64.5N and I have no clue how to get it. Dividing 83.3N by cos30 still doesn't get me 64.5N so I think I might have done something wrong in setting it up?