Speed Distance Time and Compound Measures Cheat Sheet

Key Facts

• Speed is calculated using $v = \frac{d}{t}$, where $v$ is speed, $d$ is distance, and $t$ is time.
• Distance is calculated using $d = vt$ when speed and time are known.
• Time is calculated using $t = \frac{d}{v}$ when distance and speed are known.
• Density is calculated using $\rho = \frac{m}{V}$, where $\rho$ is density, $m$ is mass, and $V$ is volume.
• Mass is calculated using $m = \rho V$, and volume is calculated using $V = \frac{m}{\rho}$.
• Pressure is calculated using $P = \frac{F}{A}$, where $P$ is pressure, $F$ is force, and $A$ is area.
• Force is calculated using $F = PA$, and area is calculated using $A = \frac{F}{P}$.
• Units must match the formula, such as $\text{m/s}$ for speed, $\text{kg/m}^3$ for density, and $\text{N/m}^2$ or $\text{Pa}$ for pressure.

Vocabulary

Speed

Speed is the distance traveled per unit of time, usually calculated with $v = \frac{d}{t}$.

Distance

Distance is the length of the path traveled, often found using $d = vt$.

Density

Density is the mass per unit volume of a substance, calculated with $\rho = \frac{m}{V}$.

Pressure

Pressure is the force applied per unit area, calculated with $P = \frac{F}{A}$.

Compound Measure

A compound measure combines two different units, such as $\text{m/s}$, $\text{g/cm}^3$, or $\text{N/m}^2$.

Rearranging a Formula

Rearranging a formula means changing its subject so a different unknown can be calculated.