Harry, the skater pulls her arms inwards but that does not contribute to her rotating motion directly. The increased speed is due to the reduction of her moment of inertia and the conservation law requires for her to spin faster so that the product of her moment of inertia and angular velocity is constant.
Dave -----Original Message----- From: H Veeder <[email protected]> To: vortex-l <[email protected]> Sent: Sun, Feb 9, 2014 1:05 pm Subject: Re: [Vo]:Linear and Angular Momentum A spinning figure skater is often used to demonstrate the principle of conservation of angular: https://www.youtube.com/watch?v=jeB4aAVQMug However, the skater also exerts some muscular energy to pull her arms inward, so doesn't this boost the angular momentum slightly? Harry
