Home · IGCSE 0625 · Motion, forces, energy · Centre of gravity · Practice
Practice questions · Centre of gravity

Steady, or about to tip.

Six original Cambridge-style questions on defining the centre of gravity, the toppling condition, what makes an object more stable, and finding the centre of gravity of a flat shape.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.
The deciding line

Topples when the weight line leaves the base.

01
[2 marks]

What is meant by the centre of gravity of an object?

  • The point at which all of the object's weight can be taken to act. ✓✓
02
Analysis
[2 marks]

State the condition under which a tilted object will topple over.

  • It topples when the line of action of its weight falls outside its base. ✓
  • While that line stays within the base, it settles back. ✓
03
Analysis
[2 marks]

State two changes that would make an object more stable.

  • Make the base wider. ✓
  • Lower the centre of gravity. ✓
04
Analysis
[3 marks]

Describe an experiment to find the centre of gravity of a flat, irregular piece of card.

  • Hang the card freely from a pin through a hole and let it settle. ✓
  • Hang a plumb line from the same pin and draw the vertical line on the card. ✓
  • Repeat from another hole; the centre of gravity is where the lines cross. ✓
05
Analysis
[2 marks]

Explain, in terms of centre of gravity and base, why a racing car is very difficult to tip over.

  • It has a low centre of gravity and a wide base. ✓
  • The car must tilt through a very large angle before the line of action of its weight reaches the edge of the base, so it rarely topples. ✓
06
Analysis
[2 marks]

A tall, narrow box and a short, wide box are made of the same material. State which is more stable and explain why.

  • The short, wide box is more stable. ✓
  • It has a lower centre of gravity and a wider base, so a much larger tilt is needed before the weight line leaves the base. ✓