# Angular velocity of suspended rod

1. Jun 26, 2016

### Prathamesh

1. The problem statement, all variables and given/known data
A uniform rod of length L & mass m is suspended through an end. It is shifted through an angle of π/2 radian i.e. made horizontal and then released. Find angular velocity when rod is vertical.

2. Relevant equations

3. The attempt at a solution
My attempt to a problem is attached
with this post.

But

Solution says
By energy conservation law
1/2 I ω2= mg L/2
(ω = angular velocity)
Hence
ω=√ (3g/L)

Which one is correct? N why other is wrong?

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2. Jun 26, 2016

### Saksham Dhull

but in your soln you have assumed that torque remains constant throughout which is wrong
You must correct it and integerate to get the right answer

3. Jun 26, 2016

### Prathamesh

Nope...i ve found the torque acting on the rod when it is in hzt position only.... and hence angular acceleration (alpha) also changes with theta...so by putting theta =π/2 i ve found w