Angular impulse

1. Apr 16, 2014

albega

1. The problem statement, all variables and given/known data
A thin rod of length L, mass m is suspended horizontally at rest. It is suddenly released and experiences immediately after an impulse vertically upwards at one end.

I need to find the maximum height reached by the centre of mass and the angular velocity of rotation about the centre of mass.

3. The attempt at a solution
I can't see how there is enough information given in the question. I have used the fact that J=0.5Lp here (J is angular momentum) from the relation between angular and linear impulse, and then this means 0.5Lmv=Iω, with I=mL2/12. Then 0.5Lmv=mL2ω/12. This relates v and ω by v=ωL/6. I could then probably work with constant acceleration formulae to get the answer, however both v and ω are unknowns (and I have to find ω in the next part) so I have no idea where to go.

2. Apr 16, 2014

Tanya Sharma

The initial velocity of CM ,angular velocity of the rod and the maximum height reached all depend upon the magnitude of impulse . So surely some data is missing from the question.

3. Apr 16, 2014

albega

Yes, as I suspected. Thanks for clarifying.

4. Apr 16, 2014

BiGyElLoWhAt

Well to me it looks as thought OP isn't supposed to solve for a number, but max height as a function of I.

5. Apr 16, 2014

BiGyElLoWhAt

Length L, mass M, impulse, I...

6. Apr 16, 2014

haruspex

Except that no label is given for the impulse in the question as stated in the OP - that's what's missing.