Re: Angular momentum

That much energy comes just from putting his arms in?  It couldent possibly
take in the order of 100N to pull a couple of lousy 3kg weights into your
sides could it? It seems to be the only explaination, certinly the first
that I thought of, but I dismised it because it seemed so unreal. This is
almost enough to get me into a bar, just to try it ;) Wouldent I be the life
of the party! hehe!



"Richard" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
>
>
> 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?
>
> The man had to do work to reel in the weights.