ROTATIONAL MOTION

How does a fixed axis constrain a rigid body's motion?

• Allows free translation
• Causes vibration
• Allows rotation and translation
• Allows only rotation about that axis

In v = ω × r, what is the direction of r?

• From particle to origin
• Tangential to path
• Perpendicular to axis
• From the origin (fixed point) to the particle

Why do internal torques sum to zero in a particle system?

• Forces are too small
• Torques are random
• Not calculated
• Internal forces act in pairs along the line joining particles

What role does the origin play in calculating angular momentum?

• Must be at center of mass
• Has no role
• Eliminates internal forces
• Reference point for position vectors

What happens to angular momentum when external torque is absent?

• It vanishes
• It doubles
• It reverses
• It stays constant