ROTATIONAL MOTION

If moment of inertia of a system decreases while rotating freely, what happens to angular momentum?

• Increases
• Decreases
• Remains constant
• Becomes zero

A rotating system has constant angular velocity. What can be said about net torque?

• Net torque is maximum
• Net torque is increasing
• Net torque is zero
• Net torque depends on inertia

Which object has the smallest moment of inertia for same mass and radius?

• Hollow cylinder
• Hollow sphere
• Solid cylinder
• Solid sphere

A solid sphere and a hollow cylinder of same mass and radius are subjected to same torque. Which has greater angular acceleration?

• Hollow cylinder
• Both same
• Solid sphere
• Depends on material

An oxygen molecule has mass 5.30×10⁻²⁶ kg and moment of inertia 1.94×10⁻⁴⁶ kg·m². If rotational KE is two-thirds of translational KE, and mean speed is 500 m/s, what is average angular velocity?

• 1.5×10¹² rad/s
• 3.4×10¹² rad/s
• 6.75×10¹² rad/s
• 9.2×10¹² rad/s