1. The problem statement, all variables and given/known data (a) suppose the coefficient of μκ between m1 and the plane in Fig 4-57 is 0.15, and that m1=m2=2.7 kg. As m2 moves down, determine the magnitude of the acceleration of m1 and m2, given θ = 25°. (b) What smallest value of kinetic friction will keep this system from accelerating? 2. Relevant equations There are many equations... For part A, ƩF = Fg - Ft +Fn Fg = mg ƩF = Fg - Ft Ff = μ(Fn) Part B, I'm not too sure. I was going to have Ft - Fg - Ff = ƩF, and have ƩF=0 because ƩF = ma, and acceleration would be 0, but then I was confused. 3. The attempt at a solution I solved Part A... the acceleration is 2.16. If you want me to go through the whole process, I will, just for the sake of time, I was hoping to just start from part B, where i'm absolutely stuck. I know that I have to set acceleration equal to zero, but when I tried I got 0.14 instead of the answer, 0.64. Any suggestions? ...and does that even make sense? Sorry, it's my first post.