Moments Lab for GCSE and A Level Physics

Build balancing beams and hanging space mobiles, pull them into motion, and solve six untimed moments and equilibrium challenges.

Learning guide and suggested activities

What this tool shows

  • How mass and perpendicular distance determine the moment of a force
  • How moving a pivot changes the balance of a uniform beam
  • How every beam in a hanging mobile must balance independently
  • The effect of beam weight, string tension and centre of mass
  • How pivots and additional angled anchor strings share support forces
  • The difference between a balanced construction and an apparatus that is moving

OCR A relevance

  • 3.2.3(a): Moment of a force and perpendicular distance
  • 3.2.3(c): The principle of moments
  • 3.2.3(d): Centre of mass and centre of gravity
  • 3.2.3(e): Equilibrium under forces and torques

AQA relevance

  • 3.4.1.2: Moments, the principle of moments and centre of mass
  • GCSE: Moments, levers and gears; balancing clockwise and anticlockwise moments

Try these tasks

  • Double one mass and predict the attachment position needed to restore balance.
  • Move the pivot off centre and investigate the beam’s own weight.
  • Add an angled anchor alongside a pivot, then measure the perpendicular moment arm of its tension.
  • Suspend a beam from two independent anchors and explore how moving a weight changes their tensions.
  • Build a mobile with three beams and check the balance of each beam separately.
  • Pull a balanced mobile, then compare its live forces with its at-rest calculations.
  • Solve the six challenges, starting with one weight and finishing with a complete mobile.

Related revision: Simple harmonic motion and damping · Inclined Plane Power Lab

MCQ practice · Problem-solving practice · All tools

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