ROTATIONAL MOTION

What is the value of total gravitational torque about the centre of gravity of a body?

• Equal to weight
• Maximum
• Negative
• Zero

In the equation τ = Σ rᵢ × mᵢg, what does rᵢ represent?

• Distance from the edge
• Radius of gyration
• Force vector on the particle
• Position vector of the i-th particle with respect to the CG

What happens if a cardboard is supported at a point other than its centre of gravity?

• It will float
• It will vibrate
• It will tilt due to unbalanced torque
• It will become heavier

Why does the cardboard not tilt when balanced at its centre of gravity?

• Because air pressure holds it
• Because it has uniform density
• Because the pencil is sharp
• Because the total gravitational torque about the CG is zero

What is the relationship between the reaction force from the pencil tip and the weight of the cardboard?

• They are perpendicular
• They act in the same direction
• They are equal and opposite
• The reaction force is half the weight