Re: Angular momentum

Timtro wrote:
> 
> I'm sorry to bother you all with this question. I was just playing around
> with a problem I found in a book. It is a simple problem where in a man sits
> on a stoll free to ratate without friction and is spun around while he holds
> two 3kg weights. we are given the moment of inertia of the man+stool,
> initial speed and the fact that the weights are 1m from the axis of
> rotation. The man then contracts his arms to 0.3m from the axis of rotation.
> Obviously the man will go faster because of this, but when I calculated the
> initial and final kinetic energies, they were VERY differant. Where did all
> that extra energy come from? Or did I calculate the energy wrong?

Angular Momentum
  http://scienceworld.wolfram.com/physics/AngularMomentum.html
  Look at equation (2)
  L is constant

Kinetic Energy
  http://scienceworld.wolfram.com/physics/KineticEnergy.html
  Look at equation (11)
  Total Energy is conserved, but Kinetic Energy is not