PHYSICS URGENT HELP please please - Two Blocks on an Incline?

Question

he figure shows two identical blocks tied together with a string which passes over a pulley at the crest of the inclined planes, one of which makes an angle q1 = 29° to the horizontal, the other makes the complementary angle q2 = 61°.
a) If there is no friction anywhere, with what acceleration do the blocks move?

a = m/s2
b) If each block has a mass m = 0.7 kg, what is the tension in the string while they are both moving?

T = N
c) Now suppose the coefficient of sliding friction between the blocks and planes is µ = 0.03. With what acceleration do the blocks move in this case?

af = m/s2

Answer 1

Start by looking at FBDs of each block

I will use motion of the block on the 61 degree
incline as positive

sin(61)*m*g-T=m*a

T-sin(29)*m*g=m*a

since they are attached by a string, then the
a is the same for both

sin(61)*m*g-m*a=T

T=sin(29)*m*g+m*a


(sin(61)-sin(29))*g/2=a

a=1.91 m/s^2

with m=0.7
T=4.67 N

C) This requires a modification of the FBDs

sin(61)*m*g-T-cos(61)*m*g*0.03=m*a

T-sin(29)*m*g-cos(29)*m*g*0.03=m*a

sin(61)*m*g-m*a-cos(61)*m*g*0.03=T

T=sin(29)*m*g+cos(29)*m*g*0.03+m*a

sin(61)*g-cos(61)*g*0.03-sin(29)*g-cos(29)*g*0.03=2*a

a=1.71 m/s^2

j