Unit 1: Kinematics

Kinematics describes motion: where something is, how fast it moves and how its speed changes, without asking why yet (the why is Unit 2, forces). Everything later in the course is built on these words, graphs and equations.

What you will master

Tell scalars (size only) from vectors (size and direction), and use a sign for direction in one dimension.
Find displacement, velocity and acceleration, and use the constant acceleration equations v = v₀ + a t x = x₀ + v₀ t + ½ a t² v² = v₀² + 2 a (x − x₀)
Read and draw position, velocity and acceleration graphs: the slope of x-t is velocity, the slope of v-t is acceleration, and the area under v-t is displacement.
Describe the same motion from different reference frames and add relative velocities.
Solve free fall and projectile problems by splitting the motion into independent horizontal and vertical parts (g = 9.8 m/s²).

Sign rule used on every page: state the positive direction first, then give every displacement, velocity and acceleration a sign.

Topics

Do them in order. Each one follows the same path: story, idea, play, worked examples, practice, common mistakes.

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Motion graphs practice

Motion graphs practice: six situations (a straight ramp, a ramp that gets steeper, rolling uphill, a hill with a flat top, a valley track and a velocity-time graph to read). Predict the distance, velocity and acceleration graphs, then press Play and watch them draw as the ball moves.

Best after topic 1.3. Watch out: these use distance graphs, which never go down, while most AP questions use position.

Labs

Interactive labs for motion graphs, from the earlier physics lab. Start here: the guided tutor, with Predict first on. Then go down the list in order. They all run in the browser and work offline.

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Suggested order: guided tutor → moving cart (try every preset and say out loud what each graph does) → 3 or 4 levels of the matching game → slope and area on the practice graphs → the sketching method, then print the practice grid and draw without the computer → free fall and the ramp → one phone experiment from the lab resources page.