IB Physics: Kinematics & the SUVAT Equations — FAQ

Identify the three variables you're given, spot the one you're asked to find, then pick the single SUVAT equation that leaves out your fifth, unused variable. According to the Physics guide (first exams 2025), kinematics sits under Topic A.1, Space, time and motion, and it appears on every exam paper.

SUVAT links displacement (s), initial velocity (u), final velocity (v), acceleration (a) and time (t) for motion with constant acceleration. The IB Physics data booklet prints four of these; a fifth, s = vt − ½at², isn't listed but can be derived and shows up often enough that it's worth memorising anyway.

Only when acceleration is constant — that's the condition students forget once the pressure's on. If a question describes changing acceleration, air resistance building up over time, or a curved velocity-time graph, SUVAT doesn't apply and you need calculus-based reasoning instead, which is mandatory content at HL.

Kinematics describes motion — displacement, velocity, acceleration — without explaining why it happens. Dynamics explains motion using forces, from Newton's laws to momentum and impulse. Both sit inside Topic A: Space, time and motion in the current guide, with kinematics (A.1) taught before forces (A.2), and exam questions regularly combine the two in one multi-part problem.

Sign errors, not equation choice. I've marked plenty of mocks where a student picks the correct formula but drops a negative sign for deceleration or downward displacement, wiping out marks on an otherwise sound method. Define which direction is positive before you write a single number down — every time.

List your knowns (u, v, a, t, s), identify which one you're asked to find, then choose the single SUVAT equation that excludes your fifth, unrequested variable. It sounds mechanical because it is — treat it as a lookup process, not something you need to 'feel out' in the exam.

At SL, no — SUVAT plus reading gradients and areas from graphs is enough. At HL, yes: the guide expects you to differentiate displacement to find velocity ($v=dx/dt$) and integrate acceleration when it isn't constant, and this shows up specifically in Paper 2 questions on non-uniform motion.

Split the motion into horizontal and vertical components and treat each as its own SUVAT problem, linked only by time. Horizontal velocity stays constant (a = 0); vertical acceleration is 9.81 m/s² downward. Solve for time using the vertical component first, then plug it into the horizontal equation.

Both. Kinematics — Topic A.1, Space, time and motion — is identical core content for SL and HL students under the current guide, first examined 2025. HL students meet the same SUVAT equations but face harder multi-step problems, plus the added expectation of calculus-based reasoning for non-uniform acceleration.

There's no fixed mark weighting published for kinematics specifically, but it appears on every paper. Expect a scaffolded 6-10 mark structured question in Paper 2, often combined with forces or projectile motion, plus 1-2 mark multiple-choice items in Paper 1 nearly every session.

All three, in different forms. Paper 1 tests it through multiple-choice and data-based items, Paper 2 through longer structured calculations often paired with forces or projectiles, and Paper 3 through practical scenarios like analysing motion-sensor data or graphing an experiment's velocity-time results.

Kinematics is one of the more accessible topics in DP Physics — the maths is algebra rather than calculus at SL — but it's also where careless sign errors cost the most avoidable marks. Students who treat it as 'easy' and skip practice often lose 2-3 marks per paper on mistakes they'd otherwise catch.

The physics itself is nearly identical — both use the same SUVAT equations and projectile-motion methods your child would meet in A-level Mechanics. The difference is context: IB folds kinematics into a broader 'Space, time and motion' theme and links it to Paper 3 practical work and the internal assessment, giving more emphasis on data analysis alongside the algebra.

Past-paper repetition beats rereading notes — you learn to spot which equation fits a scenario by getting a few wrong first, not by memorising the list in isolation. Revision notes summarising the equations and sign convention, paired with worksheets that isolate kinematics before mixing it with forces, build that pattern-recognition fastest.