This higher tier covers Higher Tier: Centre of Mass within Moments & Levers for GCSE Physics. Revise Moments & Levers in Forces for GCSE Physics with 13 exam-style questions and 10 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 11 of 14 in this topic. This section is most useful once the core foundation idea is secure, because it adds the detail that pushes answers higher.
🎓 Higher Tier: Centre of Mass
Every object has a centre of mass — the point where the entire weight of the object appears to act. For uniform regular shapes, this is the geometric centre. For irregular objects, you can find it by suspending the object from different points — the centre of mass lies along the plumb line each time.
An object topples when a vertical line through its centre of mass falls outside its base. This is why lorries can tip on steep corners: their high centre of mass means the vertical line through it exits the wheelbase, and gravity causes rotation (tipping).
In equilibrium calculations, the weight of a uniform beam acts at its midpoint — this is an important assumption used in many exam questions.
Practice questions for Moments & Levers
What is a moment?
State the principle of moments.