Compound Measures (Speed, Density, Pressure) (Cambridge (CIE) IGCSE Maths)

A compound measure is something calculated using more than one measurement, e.g. speed is calculated using distance and time.

True.

Flow rate is an example of a compound measure.

It combines two measures (volume and time) by looking at the volume of fluid that moves over time, (e.g. cm³ / s).

Population density is the measure of how many people there are per unit of area.

True.

You can use the units of a compound measure to find the equation used to calculate it.

For example, speed is often measured in km / h.
Km (kilometres) is a measure of distance and h (hours) is a measure of time, so the calculation for speed is:

False.

When using a formula triangle with a compound measure, you need to multiply the two values at the base of the triangle to find the value at the top of the triangle.

True.

Speed is the measure of how much distance changes per unit of time.

Density is the measure of how heavy something is per unit of volume or area.

False.

Pressure is measured in Pascals (Pa).

Density is measured in kg/m³.

The equation used to calculate speed is:

.

The units kg/cm³ could be used to measure density (mass per volume).