第五章 转动 03版.ppt

Find the moment of inertia of a thin uniform rod of length and mass m: (a)about a perpendicular axis through one end of the rode. (b)about a perpendicular axis through the center of the rode. (a): (b): Which tells us that : the torque on a rigid body is equal to the time rate of change of its angular momentum. Angular momentum?and linear momentum are examples of the parallels?between linear and rotational motion. They have the same form and are subject to the fundamental constraints of conservation laws, the?conservation of momentum?and the conservation of angular momentum?. A uniform rod of length L and mass M is hanging vertically with its upper end pivoted on a frictionless horizontal axis . A bullet of mass m is shot into the lower end of the rod with horizontal vertically V0 . Find the common angular speed of the rod and the bullet when staring to move together. A horizontal turntable of mass M and radius R rotating .At the edge of the table there stands a man of mass m and both are at rest relative to the ground . Find the angle turned by the table relative to the ground when the man walks for one turn along the edge the table. Since the initial angular momentum of the system is Zero: Then : and As shown , a spaceship and is spring at .The radius is r=1.5 m .The total jet flow rate q=2.0kg/s is constant .The jet speed of the exhaust is u=50 m/s and constant .How many is it need to stop the spring of the spaceship ?? When stop : The kinetic energy of a rotating object is analogous to linear kinetic energy and can be expressed in terms of the moment of inertia and angular velocity. The total kinetic energy of an extended object can be expressed as the sum of the translational kinetic energy of the center of mass and the rotational kinetic energy about the center of mass. The expressions for rotational and linear kinetic energy can be developed in