Exam 11: Angular Momentum; General Rotation

A 5.0-m radius playground merry-go-round with a moment of inertia of 2000 kg∙m² is rotating freely with an angular speed of 1.0 rad/s. Two people, each having a mass of 60 kg are standing right outside the edge of the merry-go-round and step on it with negligible speed. What is the angular speed of the merry-go-round right after the two people have stepped on?

What is the vector product of = 2.00 + 3.00 + 1.00 and = 1.00 - 3.00 - 2.00 ?

A 40.0-kg child running at a speed 3.00 m/s jumps on a stationary playground merry-go-round at a distance 1.50 m from the axis of rotation of the merry-go-round. The child is traveling tangential to the edge of the merry-go-round which has a 600 kg∙m² moment of inertia about its axis of rotation as she is running. What is the angular speed of the merry-go-round after the child jumps on it?

The total force on an object is zero. The angular momentum of the object

State the law of conservation of angular momentum for a system.

An object is rotating with an angular momentum of magnitude 20.0 kg∙m²/s in a direction directly east. A torque of magnitude 10.0 N∙m acts in a direction 30° north of east acts on the object for 5.00 s. What is the angular momentum after the torque has acted?

A playground merry-go-round with a radius of 2.0 m and a rotational inertia of 100 kg m² is rotating at 3.0 rad/s. A child with a mass of 22 kg jumps onto the edge of the merry-go-round, traveling radially inward. What is the new angular speed of the merry-go-round?

A person sits on a freely spinning lab stool (no friction). When this person extends her arms,

What is the angular momentum about the origin of a particle with a mass of 500 g when it is located at = (4 + 3 - 2 ) m and moving at = (5 - 2 + 4 ) m/s?

In general, precession results when

A bicycle is traveling north at 5.0 m/s. The mass of the wheel, 2.0 kg, is uniformly distributed along the rim, which has a radius of 20 cm. What are the magnitude and direction of the angular momentum of the wheel about its axle?

A figure skater rotating at 5.00 rad/s with arms extended has a moment of inertia of 2.25 kg∙m². If the arms are pulled in so the moment of inertia decreases to 1.80 kg∙m², what is the final angular speed?

For angular momentum to be conserved, the net force must be zero.

The position vector of an object of mass 0.50 kg subject to a constant force is given by = (at²+bt) + (ct²+dt) + (et²+ft) , where a = 2.0 m/s², b = 3.0 m/s, c = 2.5 m/s², d = -2.0 m/s, e = 1.0 m/s², and f = 4.0 m/s. What is the angular momentum of the object about the origin at t = 2.0 s?

For angular momentum to be conserved, the net torque must be zero.

A horizontal, 2.00 m long, 3.00 kg uniform beam that lies along the east-west direction is acted on by two forces. At the east end of the beam, a 200 N force pushes downward. At the west end of the beam, a 200 N force pushed upward. What is the torque about the center of mass of the beam?

A stunt motorcyclist rides his motorcycle over a short ramp so that the motorcycle loses contact with the ground. As he does this, he guns his engine and the motorcycle's front wheel is observed to rise. Explain.

A horizontal 2.00-m long, 5.00-kg uniform beam that lies along the east-west direction is acted on by two forces. At the east end of the beam, a 200-N forces pushes downward. At the west end of the beam, a 200-N force pushed upward. What is the angular acceleration of the beam?

What is the torque about the origin on a particle located at = (3 + 4 - 2 ) m exerted by a force = (5 - 2 + 3 ) N?

A force of = 3.00 N + -2.00 N acts at a location = 1.00 m + 2.00 m on an object. What is the torque that this force applies about an axis through the origin perpendicular to the xy plane?