This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: 1 Chap 11 Rolling, torque, and angular momentum Note – this is an outline of the lecture, print this and take notes on it in lecture. It is not the complete lecture. You should attend lecture to get the complete notes Images taken from Halliday/Resnick/Walker, Fundamentals of Physics, 7 th Edition, John Wiley and Sons Inc., by permission. Hints - HW 7. Use conservation of energy to find the speed at which ball leaves the roof. Remember to take account of the translational and rotational KE. Treat ball as a projectile after it has left the roof. 8. The com of the ball undergoes circular motion in the loop. The radius of this motion is R – r . The ball must have a certain minimum v to make it around the loop. Apply Newton’s 2 nd law to the ball at the top of the loop to find this v. Now apply conservation of energy. 43. This is a completely inelastic collision between two rotating objects. Since there are no external torques, angular momentum is conserved ( L i = L f ) 47. b) [angular momentum of two skaters before they grab pole] = [angular momentum after they grab pole]. d) When the two skaters pull themselves inward, their angular momentum does not change (Why?) Rolling = Translation + rotation + = Rolling and speed R dt d dt ds R s θ θ = = + = motion rotational onal translati motion Rolling R v dt dt ω = com KE of rolling lational trans rotational 2 1 2 1 2 2 com com Mv I K + = ω Static friction and rolling In order for the wheel to roll (rather than slide) there must be a friction f present....
View Full Document