AP Physics 1 Unit 1 Study GuideAP Physics 1 Unit 1 Study Guide

COLLEGE BOARD CED - COURSE FRAMEWORK V.1

AP Physics 1 -- Unit 1: Kinematics

Topics 1.1-1.5

AP Physics 1 Study Guide

AP Physics 1: Algebra-Based Course and Exam Description (College Board, Course Framework V.1)

Source used: AP Physics 1: Algebra-Based Course and Exam Description, Unit 1 "Kinematics" (Topics 1.1–1.5), plus the Science Practices, Required Equations note, and Exam Information sections of the same CED. Exam weighting: 10–15% of the multiple-choice section · Suggested pacing: ~12–17 class periods (roughly the first three weeks of the course) A note on scope: this is the shortest- weighted unit on the exam, but it is load-bearing — every later unit (dynamics, momentum, rotation, oscillations) reuses these equations and this graph vocabulary without re-teaching it. Get sloppy here and it costs you in Units 2 through 8, not just Unit 1. PART 1 — The Frame

1.1 The core model

Kinematics describes motion. It does not explain why something moves the way it does — that's Unit 2 (dynamics, forces). Unit 1 hands you a toolkit for describing position, velocity, and acceleration in four equivalent languages — diagrams, graphs, equations, and words — and the entire unit is really about becoming fluent enough to move between those four languages without losing information. That fluency is not a side skill; it's explicitly Science Practice 1 (Creating Representations) and it's the whole premise of FRQ Question 2 on the actual exam, "Translation Between Representations."

Underneath the four representations is one simplifying move: the object model. You're allowed to shrink every object to a single point and ignore its size, shape, and internal structure, tracking only properties like mass. That's what makes it legal to draw a car as a dot on a motion diagram. (You lose this simplification later in rotational units, where shape and size suddenly matter — which is a clue that Unit 1's equations are a special case of something bigger, not the whole story.)

1.2 The essential questions the CED itself opens with

College Board frames this unit around four questions worth sitting with, because they're not decorative — they map directly onto the topics: How can the idea of frames of reference allow two people to tell the truth yet have conflicting reports? → Topic 1.4 How can we estimate the height of a very tall building with only a small rock and a stopwatch? → Topics 1.2–1.3 (free fall, kinematic equations)

Why might it seem like you are moving backwards when a car passes you on the highway? → Topic 1.4 (relative velocity) Why is the rule "double your speed, quadruple your stopping distance" true? → Topic 1.3 (the v² term in the third kinematic equation) If you can answer all four with an equation and a sentence and a graph, you've basically mastered the unit.

1.3 Required vs. derived equations — a distinction the CED makes explicit that most students miss

The CED states directly: "Not all equations in this course framework appear on the equation sheet provided to students... Many of the equations in this document are provided for reference and guidance, or to demonstrate the final results of derivations expected of students." Equations tagged "Relevant equation" in the essential knowledge are generally the ones handed to you on exam day. Equations tagged "Derived equation" are things you're expected to be able to produce yourself from the given ones — they will not be sitting on your reference sheet waiting for you.

For Unit 1, concretely: the three constant-acceleration kinematic equations (below) are given to you. The component form of those equations (subscripting everything with x, for the two-dimensional case) is something you're expected to know how to construct, not something the sheet spells out for you.

1.4 Boundary statements — the exam's fine print, stated plainly

These aren't optional footnotes; they get tested directly.

Use g = 10 m/s² for any numerical problem unless told otherwise. You will not be penalized for using 9.8 or 9.81 m/s², but 10 is the College Board default and it's faster under time pressure.

AP Physics 1 does not require you to quantitatively analyze nonuniform (non-constant) acceleration — no calculus, no equations for jerk. You are expected to qualitatively describe, sketch, and discuss situations where acceleration isn't constant (e.g., a curving x-t graph whose slope keeps changing).

Relative-velocity problems (Topic 1.4) are restricted to one dimension on this exam. Don't overbuild a 2D relative-motion solution nobody's asking for.

Unless a problem says otherwise, assume the reference frame is inertial.

AP Physics 1 -- Unit 1: Kinematics 2 of 11

PART 2 — Topic-by-Topic

TOPIC 1.1 — Scalars and Vectors in One Dimension

What it actually says

A scalar is a quantity with magnitude only — distance, speed, mass, time, energy. A vector has magnitude and direction — position, displacement, velocity, acceleration, force. Vectors get an arrow over the symbol; in one dimension you drop the arrow and let the sign carry the direction entirely — that's it, that's the whole notational system for 1D vectors. A vector sum in one dimension is just signed addition: opposite directions get opposite signs, and you add.

Why this matters more than it looks like it should

Almost every kinematics error in Unit 1 traces back to sign confusion, not to not knowing an equation. Getting comfortable treating "negative" as "a direction" rather than "less than" is the actual skill being built here, and it pays off for the rest of the course (forces, momentum, and torque are all signed the same way).

Worked example

A hiker walks 300 m east, then 500 m west. Find (a) the distance traveled and (b) the displacement.

Distance is a scalar — it's the total path length: 300 + 500 = 800 m.