Finding angular acceleration of 2 masses on a rod

[umdece4]

Homework Statement

A uniform rigid rod with mass Mr = 5.9 kg, length L = 2.9 m rotates in the vertical xy plane about a frictionless pivot through its center. Two point-like particles m1 and m2, with masses m1 = 5.7 kg and m2 = 1.8 kg, are attached at the ends of the rod. What is the magnitude of the angular acceleration of the system when the rod makes an angle of 42.7° with the horizontal?

Homework Equations

all i know is that I= 1/12ML^2

The Attempt at a Solution

I honestly don't know where to star, could anyone guide me towards the right way

 

[vela]

Start by drawing a free-body diagram and identifying the forces on the rod.