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rock.freak667

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**[SOLVED] Rod...and angular acceleration**

## Homework Statement

A uniform rod AB, of length 2a and mass m, has a particle of mass 1

2m attached to B. The rod is

smoothly hinged at A to a fixed point and can rotate without resistance in a vertical plane. It is released

from rest with AB horizontal. Find, in terms of a and g, the angular acceleration of the rod when it

has rotated through an angle of [itex]\frac{\pi}{3}[/itex]

## Homework Equations

## The Attempt at a Solution

My idea is that the torque due to the weight and the mass is the net torque and that should be the same as [itex]I \alpha[/itex] where I=moment of inertia of the entire thing.

I got [itex]I=\frac{10ma^2}{3}[/itex] but I don't know how to incorporate that angle it is rotated through.