Can someone show me their work to find the answers to these problems? it's for my homework, but this screenshot shows the answers because it's a practice problem. i tried doing the practice problem with the answers to find out if i'm doing it the right way, but i can't get to the answers it's showing.

a) tension in rope = weight of B = 27N

to prevent A from sliding, friction must be >= tensions in rope = 27N

friction = weight * coeff of frict.

= (weight of A+C) * 0.2

combining

27 = (46+ min wt. of C)*0.2

min wt. of C = 135 - 46

= 89N

b) if C is removed, friction force = 46*0.15 = 6.9N

let acceleration for A and B be x, rope tension be T n gravity be g=9.8

look at free body diag for A:

tension - friction = mass A * accel

T - 6.9 = (46/g)*x

T =  (46/g)*x + 6.9

look at free body diag for B:

wt of B - tension = mass B * accel

27 - T = (27/g)*x

combining

27 - ( (46/g)*x + 6.9) = (27/g)*x

20.1 = ((27+46)/g)*x

x = 20.1*g/73

= 20.1*9.8/73

= 2.698

= 2.7 m/s^2

the maxium height is 34m/s