ROTATIONAL MOTION

Why is the CG of a ring at its centre even though there's no material there?

• It's a mistake
• Gravity is strongest there
• Because mass is symmetrically distributed around the centre
• The ring is hollow

What is the relationship between the centre of mass and the geometric centre in regular shapes?

• They are always different
• Geometric centre is heavier
• They coincide for uniform, regular shapes
• No relationship

How does the experimental method for CG work for a triangular cardboard?

• Only for squares
• By weighing
• By folding
• By suspending from vertices and drawing vertical lines

What would happen if the knife edges were replaced with rough surfaces?

• The rod would float
• No change
• The weight would decrease
• Frictional forces might introduce horizontal components

Why is the term 'homogeneous' important in Example 6.8?

• It makes the rod shiny
• It reduces cost
• It ensures uniform density and thus predictable CG location
• It increases length