IB Physics Revision

Mechanics

Kinematics, forces, momentum, work, energy and power, and measurement uncertainties.

Mechanics is a core part of IB Physics. Revise the key concepts and common mistakes below, then lock them in with the free games.

Key concepts

DisplacementVector position change (m)
Velocityds/dt (m/s, vector)
Accelerationdv/dt (m/s², vector)
SUVATv=u+at, s=ut+½at², v²=u²+2as
v-t graphslope = a, area = s
ProjectileConstant g downward
Newton 1No net force → constant velocity (inertia)
Newton 2F = ma
Newton 3Equal opposite reaction
Momentum pmv (kg m/s, vector)
ImpulseFΔt = Δp
ConservationTotal p unchanged in isolated system
Work WF · d · cosθ (J)
Kinetic energyKE = ½mv²

Common mistakes to avoid

Questions where students often pick the tempting wrong answer — make sure you know the right one:

Two balls of different mass are dropped in a vacuum — which lands first?✗ The heavier ball lands first because gravity pulls it harder.   ✓ They land together; in a vacuum all objects fall with the same acceleration.
A car moves at a steady speed in a straight line. What is the resultant force?✗ A forward force, because it keeps moving.   ✓ Zero — the forces are balanced at constant velocity.

Practise Mechanics — free games

Test yourself with these quick revision games for this topic:

▶ Two Truths, One Lie▶ Reveal Race▶ Connections Grid▶ Falling Words▶ Word Web

See all 17 games in the Subjects Arcade →

More IB Physics topics

Thermal PhysicsWavesElectricity & MagnetismFields & GravitationAtomic, Nuclear & QuantumEnergy ProductionAstrophysics

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