IB Physics Data Booklet Key Equations Reference Cheat Sheet

Key Facts

• For constant acceleration, the kinematics equations include $v = u + at$, $s = ut + \frac{1}{2}at^2$, and $v^2 = u^2 + 2as$.
• Newton's second law is $F = ma$, where the net force $F$ causes acceleration $a$ of a mass $m$.
• Kinetic energy is $E_k = \frac{1}{2}mv^2$, and gravitational potential energy near Earth's surface is $E_p = mgh$.
• Power is the rate of energy transfer, so $P = \frac{\Delta E}{\Delta t}$, and mechanical power can also be written as $P = Fv$ when force and velocity are parallel.
• The wave equation is $v = f\lambda$, where $v$ is wave speed, $f$ is frequency, and $\lambda$ is wavelength.
• For an ideal gas, $pV = nRT$, and the average translational kinetic energy per molecule is $\frac{3}{2}k_B T$.
• Ohm's law is $V = IR$, electric power can be calculated using $P = VI$, $P = I^2R$, or $P = \frac{V^2}{R}$.
• Photon energy is $E = hf = \frac{hc}{\lambda}$, linking quantum energy, frequency, and wavelength.

Vocabulary

Net force

The vector sum of all forces acting on an object, which determines its acceleration through $F = ma$.

Work

Energy transferred by a force acting through a displacement, calculated as $W = Fs\cos\theta$.

Specific heat capacity

The energy required to raise the temperature of $1\,\text{kg}$ of a substance by $1\,\text{K}$, given by $Q = mc\Delta T$.

Frequency

The number of wave cycles passing a point per second, measured in hertz and related to period by $f = \frac{1}{T}$.

Electric field strength

The force per unit positive charge at a point in a field, defined by $E = \frac{F}{q}$.

Photon

A packet of electromagnetic radiation with energy $E = hf$.