- #1
Alexander350
- 36
- 1
Homework Statement
Homework Equations
Angular momentum = moment of inertia * angular velocity
Change in angular momentum = impulsive moment
[itex]v^2=u^2+2as[/itex]
The Attempt at a Solution
First I used [itex]v^2=u^2+2as[/itex] to find the velocity of the particle the moment the string goes taut. I got [itex]v=\sqrt{8ag}[/itex]. Then I put [itex]m\sqrt{8ag}a=\frac{1}{2}ma^2\dot{θ}[/itex] because I thought the moment of the impulse by the particle should equal the change in angular momentum of the pulley wheel. However the solution I have has [itex]m\sqrt{8ag}a=\frac{1}{2}ma^2\dot{θ}+(ma\dot{θ})a[/itex] with an extra term. I am not sure why; isn't [itex]a\dot{θ}[/itex] equal to the velocity of a point on the rim of the wheel, and not the particle? After the string goes taunt, why does the particle have angular momentum at all if it is not rotating?