Exam 11: Angular Momentum; General Rotation

Two nonparallel vectors determine a plane. Relative to the plane determined by the position vector and velocity vector of a particle, in which direction is the angular momentum vector about the origin?

An object is rotating with an angular momentum 4.00 kg∙m²/s while being acted on by a constant torque 3.00 N∙m . What is the angular speed of precession of the angular velocity of the object?

Two nonparallel vectors determine a plane. Relative to the plane determined by the position vector where the force is applied and the force vector, in which direction is the torque vector about the origin?

Vector cross products are not commutative.

A merry-go-round spins freely when Janice moves quickly to the center along a radius of the merry-go-round. It is true to say that

What is the vector product of = 5.00 + 3.00 and = -2.00 + 4.00 ?

A force at = 4.00 N - 3.00 N is applied to an object at position = 2.00 m + 3.00 m . What is the torque about the origin?

What is the magnitude of the vector product of a vector of magnitude 20.0 pointing east and a vector of magnitude 30.0 pointing 30.0° north of east?

A figure skater is spinning slowly with arms outstretched. She brings her arms in close to her body and her angular speed increases dramatically. The speed increase is a demonstration of

If you cross a vector with itself, the resultant will be a unit vector.

State the law of conservation of angular momentum for a rotating object.

A 2.00-kg mass is located at = 2.00 m + 3.00 m and has velocity = 4.00 m/s - 1.00 m/s . What is the angular momentum of the mass?

A playground merry-go-round with a radius of 1.8 m and a rotational inertia of 120 kg m² is stationary. A child with a mass of 25 kg gets on and walks around the edge of the merry-go-round. How many revolutions around the merry-go-round must the child make in order for the merry-go-round to make one full revolution?

A child is riding near the outer rim of a freely-rotating playground merry-go-round. What happens if the child walks towards the center?

The time rate of change of the total angular momentum of a system of particles equals the resultant external torque on the system.

A child runs and jumps tangentially onto an initially stationary playground merry-go-round. As a result, the merry-go-round begins to turn. Explain in terms of the child-merry-go-round system.

An ice skater has a moment of inertia of 5.0 kg∙m² when her arms are outstretched. At this time she is spinning at 3.0 revolutions per second (rps). If she pulls in her arms and decreases her moment of inertia to 2.0 kg∙m², how fast will she be spinning?

Angular momentum cannot be conserved if

What is the vector product of = (4 - 3 - 5 ) and = (5 - 4 + 2 )?

A 2.00-kg sphere is rotating about an axis through its center at 40.0 rev/s with the angular velocity in the +z direction. A torque 10.0 N∙m acts on the sphere about the center of the sphere in the +x direction. What is the rate of change of the angular momentum of the sphere?