AP Physics 2 Formulas

First Law of Thermodynamics

ΔU=Q−W

• ΔU\Delta UΔU = change in internal energy (J)

• Q = heat added to the system (J)

• W = work done by the system (J)

Work in Gas Expansion

W=PΔV

• P = pressure (Pa)

• ΔV = change in volume (m³)

Heat Transfer Equations (a) Conduction

Q = (kAΔT​/d)t

• k = thermal conductivity

• A = cross-sectional area

• d = thickness

• t = time

Heat Transfer Equations (a) Radiation

Q=σ(AT)^4 t

• σ= Stefan–Boltzmann constant

• A = cross-sectional area

• t = time

Specific Heat Capacity

Q=mcΔT

• m = mass (kg)

• c = specific heat (J/kg·K)

• ΔT = change in temperature

Phase Changes

Q=mL

• L = latent heat (fusion, vaporization, etc.)

• m = mass (kg)

Electric Force — Coulomb’s Law

F=ke​ ∣q1​q2​∣​ / r²

• F = electric force (N)

• q1,q2​ = charges (Coulombs, C)

• r = distance between charges (m)

• ke=8.99×10^9 N

Electric Field

E=q/F​ or ke* (Q/r²)

• E = electric field (N/C)

• F = force on a test charge (N)

• q = test charge (C)

• Q = source charge creating the field (C)

Electric Potential (Voltage)

V=q/U​ or ke​ (Q/r)​

• V = electric potential (Volts, J/C)

• Energy per unit charge.