Exam 11: Angular Momentum; General Rotation

You are walking holding on to the axle of a spinning bicycle wheel with one hand on either side of the wheel. The top part of the wheel is moving away from you and the bottom is moving toward you and the axle is horizontal. As you start to turn left, you feel the right side of the axle

The boom of a crane is 20 m long and is inclined 20° from the horizontal. A bucket of cement with a mass of 3000 kg is suspended from the upper end of the boom. What is the torque acting on the point where the boom is attached to the crane?

A flywheel with a moment of inertia 6.00 × 10⁶ kg∙m² is spinning with an angular speed of 120 rev/s about a vertical axis while it sits at the north pole. The disk is turning counterclockwise when viewed from above. The disk is brought to a rest. Treat the earth as a uniform sphere with a mass 5.976 × 10²⁴ kg and a radius 6.374 × 10⁶ m. (a) What will be the magnitude of the change in angular momentum of the earth? (b) What will be the change in length of a day on Earth?

A uniform 2.00-kg circular disk of radius 20.0 cm is rotating clockwise about an axis through its center with an angular speed 30.0 revolutions per second. A second uniform 1.50-kg circular disk of radius 15.0 cm that is not rotating is dropped onto the first disk so that the axis of rotation of the first disk passes through the center of the second disk. What is the final angular speed of the two disks when they are rotating together?

You are holding a finishing sander with your right hand. The sander has a flywheel which spins counterclockwise as seen from behind the handle. You are sanding a wall in front of you. As you turn the sander towards the right, you feel a tendency in the sander to