ROTATIONAL MOTION

What is the condition for a system to have constant angular momentum?

• Net external force is zero
• All torques are internal
• Net external torque is zero
• The body is spherical

What is the physical significance of the cross product in angular momentum?

• It makes L parallel to motion
• It reduces magnitude
• It ensures L is perpendicular to the plane of motion
• It converts to energy

How does the conservation of angular momentum apply to a binary star system?

• They repel each other
• They emit light to conserve L
• Their mutual gravitational force is internal and central, so L is conserved
• Internal friction removes angular momentum

What is the effect of doubling the force on the torque, if r and angle are constant?

• Torque halves
• Torque unchanged
• Torque quadruples
• Torque doubles

What is the relationship between the total angular momentum and the center of mass?

• They are always equal
• L is zero at COM
• L can be split into orbital and spin parts relative to COM
• COM has no angular momentum