In a famous Physics 218 experiment a student stands on a platform which is free to rotate on frictionless bearings. The moment of inertia of the platform about the vertical axle through its center is a known constant I. He has his arms extended with a huge mass m in each hand. If he is set into rotation with angular velocity w, and then drops his hands to his sides, what happens to his angular velocity? Assume that the man's mass is negligible and that his arms have length d when extended and are d/4 from the center of his body when at his sides. @o т т Call the angular velocity that you found @, . Now the instructor applies a constant decelerating force F, to the edge of the platform that is directed as shown. How long will it take for the platform to come to stop after the force is applied? The radius of the platform is R. View from above Fo Fo

In a famous Physics 218 experiment a student stands on a platform which is free to rotate on frictionless bearings. The moment of inertia of the platform about the vertical axle through its center is a known constant I. He has his arms extended with a huge mass m in each hand. If he is set into rotation with angular velocity w, and then drops his hands to his sides, what happens to his angular velocity? Assume that the man's mass is negligible and that his arms have length d when extended and are d/4 from the center of his body when at his sides. @o т т Call the angular velocity that you found @, . Now the instructor applies a constant decelerating force F, to the edge of the platform that is directed as shown. How long will it take for the platform to come to stop after the force is applied? The radius of the platform is R. View from above Fo Fo