Newton's Law Questions are posed.

I need help setting up and working through three more problems. Most of them I have attempted but could not make them work. Any help is appreciated!

Blocks of equal mass M sits on a plane inclined at 30 degrees to the horizontal. The coefficient of friction between the lower block (A) and the plane is 0.50 and between the upper block (B) is 0.30. (a) Find the acceleration of each block and the normal force exerted on A by B (b) What happens if the two blocks are reversed do that B leads the way down?

See attached file for full problem description.

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... (2)

and resolving perpendicular to the plane yields

(3)

substitute (3) into (1) and (2), and adding (1) and (2) gives:

but since each block moves together, the acceleration of each is the same. So;

putting in numbers gives a = 3.01 m/s

b) As mentioned above, if block B is lower than block A, it's lower coefficient of friction means it will want to move faster, so each block will move independently.
Question:
(a) Pulleys in the system are massless and frictionless, what mass m must the ball have if it is to support the cylinder of mass M?
(b) if m=M, find the acceleration of each of the objects?

a) The tension in each part of the string is the same, as there is only 1 string connected through the pulleys.

The cylinder is ...