A block of mass M1 resting on a 18.8 slope is shown. The block has coefficients of friction _s = 0.647 and _k = 0.388 with the surface. It is connected via a massless string over a massless, frictionless pulley to a hanging block of mass M2 = 2.49 kg.

a)what is the minimum mass M1 that will remain stationary and not slip?

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?