Show your answers and how you got them. You seem to misunderstand this forum. People here will go out of their way to help you learn how to solve problems, but you are asking to be simply spoon-fed answers and that doesn't fly here.
In order to complete physics hw, being spoon-fed answers just doesn't cut it. Amongst all subjects, physics requires work shown AND an answer to even remotely do well in class.
So if you're concerned that I'll just take your answers and run with them and put them on my worksheet and call them my own, it seems a bit redundant because I wouldn't even get a good grade on the homework.
So I don't think "spoon-fed" is the correct term here; I don't think cynical behavior can exist when just asking for answers to a physics worksheet.
Problem 3 (Previous Problems were 1 and 2):
Acceleration (A) = -Acceleration (B)
T - m(A)g = 5a(A)
T - m(B)g = 4a(B)
T - 50 = 5a(A) -----> 50 - T = -5a(A) = 5a(B)
T - 40 = 4a(B)
10 = 9a(B)
Acceleration of B = 10/9
Acceleration of A = -10/9
FBD of mass m =
-Force of mg downwards
-Force of μ(s)F(app) upwards to cancel out mg
-Force applied to the right
-Opposite normal force (N1) exerted by mass M to the left
μ(s)F(app) = 50
F(app) = 125
Acceleration of mass A = Acceleration of mass B (downwards is considered negative in the case of mass B for convenience)
20 - T = 2a(B)
T - μ(k)m(A)g = 2a(A)
T - 4 = 2a(A)
16 = 4a
a(A and B) = 4m/s^s
T = 12N
(mass of C and A)g + [(mass of B)(g) - T] = Normal Force of system
70 + 20 - 12 = 78
(Normal Force system)μ(s) = (Normal Force of A on C)μ(k)
78μ(s) = 4
μ(s) = 0.5128
People here generally go out of their way to be helpful but you are making this difficult. I would suggest that you ask a moderator to delete this thread and then you start a new thread for each of your problems, showing all of your work for the problem in one place with the statement of the problem. the way you have it now, you are asking people to go to a bit of trouble just to figure out what you've done so far. You might get lucky and someone will go to the trouble, but you'd likely have more luck if you separate the problems.