ROTATIONAL MOTION

How does the concept of mechanical equilibrium apply to buildings and bridges?

• They are always moving
• They ignore physics
• They are designed to have zero net force and torque under load
• They float

How does the angular momentum of a system respond to external torque?

• It stays the same
• It vanishes
• It changes at a rate equal to the applied torque
• It oscillates

Why can a body in equilibrium have forces acting on it?

• Forces cannot act
• Only one force acts
• Because the vector sum of all forces and torques is zero
• They are imaginary

What is the role of the right-hand rule in rotational dynamics?

• It measures force
• It stops motion
• It determines the direction of cross product vectors like torque and angular momentum
• It changes mass

How does the equilibrium of a rigid body differ from that of a particle?

• They are identical
• Particle needs more conditions
• A rigid body must satisfy both force and torque balance, while a particle only needs force balance
• Rigid bodies cannot be in equilibrium