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Here is the problem:

Three masses, (m1 = 3.0kg, m2 = 1.0kg, m3 = 2.0kg), all in the x-y plane, are connected to each other by rigid rods of negligible mass. They are also connected to a bearing on the axis of rotation, the z-axis, by a similar rigid rods of length r1 = 0.40m, r2 = 0.60m, and r3 = 0.20m, respectively to the masses. The rod r1 makes an angle of 30 degrees with the negative x-axis, r2 makes an angle of 60 degrees with the positive x-axis, and r3 lies along the positive x-axis. The assembly of masses is held stationary with r3 horizontal and then released. (Gravity is acting on the system to cause it to rotate)

a) Find the angular acceleration of the assembly just after release

b) Find the linear tangential accelerations of each mass.

Here's a pic for clarification:

I planned on using the fact that Torque = Rotational Inertia * rotation acceleration. I calculated the total rotational inertia to be .92 (by using I=m1*r1^2 + m2*r2^2 + m3*r3^2). And I tried calculating total torque by T1+T2+T3, assuming T=r*F*sin(Theta), and F would be mass*cos(theta)*9.81. That didn't get me the answer I was looking for.

The answer to part a is 3.62 rad/s^2 but I did'nt get there.

Part b is easy as soon as I can finish part a.

Thanks for any help!