Question

can anyone help please?

Answer 1

Two small rings, A and B, each of mass 2m, are threaded on a rough horizontal pole. The
coefficient of friction between each ring and the pole is µ. The rings are attached to the ends of
a light inextensible string. A smooth ring C, of mass 3m, is threaded on the string and hangs in
equilibrium below the pole. The rings A and B are in limiting equilibrium on the pole, with
<BAC = <ABC = theta, where tan theta = 3/4

(a) Show that the tension in the string is 5/2 mg.

(b) Find the value of µ.

Answer 2

i did the a part and found that tension in the string is
3mg/2sin(theta), which gives 2.5mg or 5/2mg

but how to find the friction coefficient???