Need help with (b)

Suppose there is a block of mass M1 resting on a 18.9 slope. The block has coefficients of friction _s = 0.754 and _k = 0.403 with the surface. It is connected via a massless string over a massless, frictionless pulley to a hanging block of mass M2 = 2.84 kg.

a) What is the minimum mass M1 that will remain stationary and not slip? (Ans: 2.74 kg)

b) If this minimum mass is nudged ever so slightly, it will start being pulled up the incline. What magnitude of acceleration will the minimum mass have?