# Homework Help: Qn. on general rotational mechanics

1. Nov 14, 2012

### manogna08

1. The problem statement, all variables and given/known data

a uniform rod of mass m nd length 2l lies on smooth horizontal surface. a particle of mass m is connected to a string of length l whose other end is connected to one of the ends of the rod. initially string is taut and both string and rod lie in same plane with 90 angle b/w them. if particle is given velocity v perpendicular to string, then jus after givin velocity find tension in string and angular acceleration of rod.

2. Relevant equations

3. The attempt at a solution
i tried using ζ = Iα about centre of mass but could not succeed..plzz help.....

2. Nov 14, 2012

### lewando

I would think that when the velocity was imparted to the particle, since is it attached to the rod via a string (assumed inextensible, otherwise it's a spring) then the same velocity would be imparted to the end of the rod.

3. Nov 14, 2012

### haruspex

No, the particle is driven perpendicularly to the string.
Always start by creating some names for unknowns that might be relevant:
T = tension
α = angular acceleration of rod
a = linear acceleration of rod.
Then draw the free body diagram and try to write down some equations using the conservation laws. Post whatever you come up with.

4. Nov 14, 2012

### lewando

That makes for a more interesting problem. Reading is fundamental .