ROTATIONAL MOTION

In which situation is angular momentum conserved?

• When net external force is zero
• When velocity is constant
• When acceleration is zero
• When net external torque acting on the system is zero

What is the direction of torque in the bicycle rim experiment when one string is released?

• Same as angular momentum
• Downward
• Along the string
• Perpendicular to both the angular momentum vector and the gravitational force

What determines the magnitude of angular momentum of a particle?

• r + p
• r × p (as scalar)
• r / p
• Product of magnitude of position vector, linear momentum, and sine of angle between them

How is the total angular momentum of a system affected by internal torques?

• They increase the total angular momentum
• They decrease it to zero
• They randomize its direction
• Internal torques cancel out and do not affect total angular momentum

Why doesn't the rotating bicycle rim fall under gravity when one string is cut?

• Because angular momentum cancels gravity
• Because the rim becomes weightless
• Because tension increases
• Because the torque leads to precession, not toppling