ROTATIONAL MOTION

What happens to the angular momentum vector during precession?

• It becomes zero
• It reverses periodically
• It points vertically upward
• It rotates in a horizontal circle

Why does the rotating bicycle rim not immediately fall when one string is cut?

• The rim becomes weightless
• Air pressure supports it
• Centrifugal force balances gravity
• The torque changes the direction of angular momentum instead of causing translational motion

What determines the direction of the torque acting on the bicycle rim when one string is released?

• Direction of angular velocity
• Magnitude of linear momentum
• Tension in the remaining string
• The cross product of position vector from pivot to center of mass and gravitational force

In the bicycle rim experiment, what role does the extended axle play?

• It reduces air resistance
• It increases the mass of the system
• It prevents rotation
• It allows strings to be attached at both ends for stable suspension

How is the total angular momentum of a system related to external torque?

• Total angular momentum is always zero
• It is independent of torque
• It equals the sum of internal torques
• The rate of change of total angular momentum equals the net external torque