Acceleration using kinetic friction

[joedozzi]

Part A: A block of mass M resting on a 18.8° slope is shown. The block has coefficients of friction μs=0.620 and μk=0.314 with the surface. It is connected via a massless string over a massless, frictionless pulley to a hanging block of mass 2.97 kg. What is the minimum mass M1 that will stick and not slip?

I have figured this part out.. the mass is 3.27kg

Now I need this mass in order to complete this question
Part B: If this minimum mass is nudged ever so slightly, it will start being pulled up the incline. What acceleration will it have?

I tried using this equation and plugged in all my variables but I must be missing something.

Formula: m1a + m2a = m2g - m1gsin(theta) - ukm1gcos(theta)

 

[tiny-tim]

hi joedozzi!

(have a mu: µ and a theta: θ and try using the X₂ icon just above the Reply box )

Part A: A block of mass M resting on a 18.8° slope is shown. The block has coefficients of friction μs=0.620 and μk=0.314 with the surface. It is connected via a massless string over a massless, frictionless pulley to a hanging block of mass 2.97 kg. What is the minimum mass M1 that will stick and not slip?
…
Formula: m1a + m2a = m2g - m1gsin(theta) - ukm1gcos(theta)

looks ok to me

(that's for being pulled uphill … is this uphill or downhill?)