Problem 9: The rotational inertia of a collapsing spinning star drops from an initial value Ii= 9 x 1099 kg m2 to a value of If = 3 x 1099 kg m2. (a) Ratio of final rotational kinetic energy (KEf) to the initial rotational KEi is ________ (b) What would that ratio be if If/Ii=1/4? ________

Newton's second law for linear motion is mà The equivalent form for rotational motion is - là, where is torque, I stands for the moment of inertia, and is the angular acceleration. The effectiveness of the applied torque is determined by: O The amount of Force applied The distance of the applied force from the axis of rotation. O The angle between the applied force vector Fand the vector distance from the axis of rotation to the applied point of the force O All of the above

W; = 0 %3D Wf initial final A flywheel consists of a thin uniform disk of mass m and radius R, free to rotate about a frictionless central axle. A small weight, also of mass m, is attached to the wheel's rim. The is wheel is held at rest (left), the small weight level with the axle, then released. What is the angular velocity of the wheel when the weight reaches its lowest point? 4g V 3R 8g V 5R 3g V 2R V28R 2gR

A baseball has a mass of 0.15 kg and radius 3.7 cm. In a baseball game, a pitcher throws the ball with a substantial spin so that it moves with an angular speed of 37 rad/s and a linear speed of 51 m/s Assuming the baseball to be a uniform solid sphere, determine the rotational and translational kinetic energies of the ball in joules. КЕ Frotational KEtranslational