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AP Physics Cheat Sheet 2026
Key equations and concepts for AP Physics 1, 2, and C · Updated for 2026 exam
The AP Physics exams provide a formula sheet on exam day. This cheat sheet covers the most-tested equations across all AP Physics courses, with notes on when and how 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. Components are independent.
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 force; $\mu_k$ for kinetic, $\mu_s$ for static (max) |
| $F = -kx$ | Spring (Hooke's Law); $x$ = displacement from equilibrium |
| $F_g = G\frac{m_1 m_2}{r^2}$ | Universal gravitation; $G = 6.67\times10^{-11}$ |
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 $r$ and $F$ |
| $\tau_{net} = I\alpha$ | 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 |
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 |
| $T_{spring} = 2\pi\sqrt{\frac{m}{k}}$ | Period of mass-spring system |
| $f_{beat} = |f_1 - f_2|$ | Beat frequency |
Fluids P1 P2
| Equation | Notes |
|---|
| $P = P_0 + \rho g h$ | Pressure at depth $h$ |
| $F_b = \rho_{fluid} g V_{sub}$ | Buoyant force = weight of displaced fluid |
| $A_1 v_1 = A_2 v_2$ | Continuity equation; narrower pipe → faster flow |
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 |
| $V = IR$ | Ohm's Law |
| $P = IV = I^2R$ | Power in a resistor |
| Series: $R_{total} = R_1 + R_2 + \cdots$ | Same current through all |
| Parallel: $\frac{1}{R_{total}} = \frac{1}{R_1} + \frac{1}{R_2} + \cdots$ | Same voltage across all |
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 |
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