A 2 kg box, m1, on a 30˚ inclined plane is attached to a 5 k…

A 2 kg box, m1, on a 30˚ inclined plane is attached to a 5 kg hanging mass, m2.  The coefficient of kinetic friction between the box and the surface is µk = 0.2.  (a) What is the magnitude of the acceleration of the box?   m/s2   (b) What is the tension in the string?     (c) What would the coefficient of static friction need to be for the box to remain stationary on the incline, i.e. not slide up or down the incline. (Round to the thousandths place)     (d) What is the tension in the string in the case found in part (c)?