AP Physics Cheat Sheet 2026
The most-tested equations across all AP Physics courses, organized by topic with notes on when to apply each one. Badges show which course each formula appears on: P1 = Physics 1, P2 = Physics 2, PC = Physics C.
Kinematics P1 PC
| Equation | Use when you know |
|---|---|
| $v = v_0 + at$ | No displacement needed |
| $x = x_0 + v_0 t + \frac{1}{2}at^2$ | No final velocity needed |
| $v^2 = v_0^2 + 2a\Delta x$ | No time needed |
| $\bar{v} = \frac{v + v_0}{2}$ | Constant acceleration only |
Projectile motion: Horizontal ($a=0$): $x = v_{0x}t$. Vertical ($a = -g$): use kinematics above with $g = 9.8$ m/s². The two components are completely independent.
Kinematics Example
Problem: A ball is launched horizontally at 12 m/s from a 20 m cliff. How far does it travel horizontally before hitting the ground?
Step 1 — Find time: Vertical: $20 = \frac{1}{2}(9.8)t^2 \Rightarrow t = 2.02$ s
Step 2 — Horizontal distance: $x = v_{0x} \cdot t = 12 \times 2.02 = \mathbf{24.2 \text{ m}}$
Forces & Newton's Laws P1 PC
| Equation | Notes |
|---|---|
| $F_{net} = ma$ | Net force = sum of all forces on the object |
| $F_g = mg$ | Weight; $g = 9.8$ m/s² near Earth's surface |
| $F_f = \mu F_N$ | Friction; use $\mu_k$ for kinetic, $\mu_s$ for static (max) |
| $F = -kx$ | Hooke's Law; $x$ = displacement from equilibrium |
| $F_g = G\frac{m_1 m_2}{r^2}$ | Universal gravitation; $G = 6.67\times10^{-11}$ N·m²/kg² |
Forces Example
Problem: A 5 kg block is pushed across a surface with $\mu_k = 0.3$. Applied force = 25 N. Find acceleration.
$F_N = mg = 5 \times 9.8 = 49$ N
$F_f = \mu_k F_N = 0.3 \times 49 = 14.7$ N
$F_{net} = 25 - 14.7 = 10.3$ N
$a = F_{net}/m = 10.3/5 = \mathbf{2.06 \text{ m/s}^2}$
Circular Motion & Rotation P1 PC
| Equation | Notes |
|---|---|
| $a_c = \frac{v^2}{r}$ | Centripetal acceleration; always points toward center |
| $F_c = \frac{mv^2}{r}$ | Net centripetal force — provided by friction, tension, gravity, etc. |
| $\tau = rF\sin\theta$ | Torque; $r$ = lever arm, $\theta$ = angle between $\vec{r}$ and $\vec{F}$ |
| $\tau_{net} = I\alpha$ | Rotational Newton's 2nd law |
| $L = I\omega$ | Angular momentum; conserved when $\tau_{net} = 0$ |
Energy & Work P1 P2 PC
| Equation | Notes |
|---|---|
| $W = Fd\cos\theta$ | Work done by a constant force |
| $KE = \frac{1}{2}mv^2$ | Translational kinetic energy |
| $KE_{rot} = \frac{1}{2}I\omega^2$ | Rotational kinetic energy |
| $PE_g = mgh$ | Gravitational PE; reference point is your choice |
| $PE_s = \frac{1}{2}kx^2$ | Spring PE |
| $W_{net} = \Delta KE$ | Work-energy theorem |
| $P = \frac{W}{t} = Fv$ | Power |
Energy Example
Problem: A 2 kg ball drops from rest at height 5 m. Find its speed just before hitting the ground.
Use energy conservation: $PE_i = KE_f$
$mgh = \frac{1}{2}mv^2 \Rightarrow v = \sqrt{2gh} = \sqrt{2 \times 9.8 \times 5} = \mathbf{9.9 \text{ m/s}}$
Momentum & Impulse P1 PC
| Equation | Notes |
|---|---|
| $p = mv$ | Linear momentum |
| $J = F\Delta t = \Delta p$ | Impulse = change in momentum |
| $p_{before} = p_{after}$ | Conservation of momentum (no external forces) |
| Elastic collision | Both $p$ and $KE$ conserved |
| Perfectly inelastic | Objects stick together; only $p$ conserved |
Waves & Simple Harmonic Motion P1 P2
| Equation | Notes |
|---|---|
| $v = f\lambda$ | Wave speed |
| $T = \frac{1}{f}$ | Period and frequency are reciprocals |
| $T_{pendulum} = 2\pi\sqrt{\frac{L}{g}}$ | Period of simple pendulum; independent of mass and amplitude |
| $T_{spring} = 2\pi\sqrt{\frac{m}{k}}$ | Period of mass-spring system; independent of amplitude |
| $f_{beat} = |f_1 - f_2|$ | Beat frequency between two sources |
Fluids P1 P2
| Equation | Notes |
|---|---|
| $P = P_0 + \rho g h$ | Pressure at depth $h$; increases linearly with depth |
| $F_b = \rho_{fluid} g V_{sub}$ | Buoyant force = weight of displaced fluid (Archimedes) |
| $A_1 v_1 = A_2 v_2$ | Continuity equation; narrower pipe → faster flow |
| $P_1 + \frac{1}{2}\rho v_1^2 + \rho g h_1 = P_2 + \frac{1}{2}\rho v_2^2 + \rho g h_2$ | Bernoulli's equation (P2) |
Electricity P2 PC
| Equation | Notes |
|---|---|
| $F = k\frac{q_1 q_2}{r^2}$ | Coulomb's Law; $k = 9\times10^9$ N·m²/C² |
| $E = k\frac{q}{r^2}$ | Electric field from point charge; direction away from + charge |
| $V = IR$ | Ohm's Law |
| $P = IV = I^2R = \frac{V^2}{R}$ | Power in a resistor |
| Series: $R_{total} = R_1 + R_2 + \cdots$ | Same current; voltages add |
| Parallel: $\frac{1}{R_{total}} = \frac{1}{R_1} + \frac{1}{R_2} + \cdots$ | Same voltage; currents add |
Key Constants
| Constant | Value |
|---|---|
| $g$ (near Earth) | $9.8$ m/s² |
| $G$ (universal gravitation) | $6.67 \times 10^{-11}$ N·m²/kg² |
| $k$ (Coulomb) | $9.0 \times 10^9$ N·m²/C² |
| $e$ (electron charge) | $1.6 \times 10^{-19}$ C |
| $c$ (speed of light) | $3.0 \times 10^8$ m/s |
| $h$ (Planck) | $6.63 \times 10^{-34}$ J·s |
Common AP Physics Exam Tasks
- Draw a free-body diagram — label every force with direction and a clear name. Missing a force costs points even if your math is right.
- Apply Newton's 2nd law — set up $\Sigma F = ma$ for each axis separately. Choose a positive direction and stay consistent.
- Use energy conservation — identify initial and final states, write $E_i = E_f$ (or $E_i + W_{ext} = E_f$ if friction or external work is present).
- Conservation of momentum — applies in all collisions. For explosions and perfectly inelastic collisions, momentum is conserved even though KE is not.
- Experimental design FRQ — identify variables, describe measurement procedure, explain how to minimize error. This question type appears on every Physics 1 exam.
- Justify your answer in words — Physics 1 FRQs often ask you to "explain" or "justify." A correct number with no explanation earns partial credit at best.
How to Study AP Physics Effectively
- Understand before memorizing — the formula sheet is provided, so rote memorization is the wrong strategy. Focus on knowing when and why each equation applies.
- Draw every problem — sketching a free-body diagram or energy diagram before writing equations reduces setup errors significantly.
- Practice FRQs with the rubric open — College Board releases FRQs with scoring guidelines. Read what earns points, especially on justification questions.
- Master the multi-select MC — 5 questions require two correct answers with no partial credit. These are high-stakes; spend extra time on them.
- Work through past exams timed — time management is a real issue on Physics 1. 90 minutes for 50 MC questions means under 2 minutes per question.
Frequently Asked Questions
Do you get a formula sheet on AP Physics 1?
Yes. AP Physics 1, AP Physics 2, and both AP Physics C exams provide an official equation sheet. However, it only lists equations — it doesn't tell you which one to use, how to set up the problem, or what the variables mean in context.
What equations are most important for AP Physics 1?
The highest-frequency equations are $F_{net} = ma$, the four kinematics equations, $W = \Delta KE$, $p = mv$, and conservation of momentum. These appear on nearly every exam. Torque and rotational motion also carry significant weight.
Why is AP Physics 1 so hard if you get a formula sheet?
AP Physics 1 has a ~45% pass rate because the exam tests conceptual reasoning, not formula recall. Most FRQ points come from explaining your reasoning, justifying your approach, and correctly identifying what's physically happening — not from plugging numbers into equations.
What is the difference between AP Physics 1 and AP Physics C?
AP Physics 1 is algebra-based and covers mechanics, waves, and basic circuits. AP Physics C: Mechanics is calculus-based and covers the same mechanics content with integration and differentiation. Physics C requires a strong calculus background and is significantly more mathematically rigorous.
Full Formula Sheets by Course
- AP Physics 1 Formula Sheet — Complete Reference
- AP Physics 2 Formula Sheet — Complete Reference
- AP Physics C: Mechanics Formula Sheet