Key concepts of physics Study Guide

In science, measurements can vary greatly in scale, from very large distances to extremely tiny particles. To simplify the representation of these numbers, we use prefixes. These prefixes are standardised multipliers or sub-multipliers that are added to base units like metres (m), seconds (s), or grams (g). For example, 'kilo' means 1000 times the base unit, so a 'kilometre' is 1000 metres. Similarly, 'milli' means one-thousandth of the base unit, making a 'millimetre' 0.001 metres. Understanding these prefixes is crucial for accurate calculations and communicating scientific data effectively.

The International System of Units (SI) provides a globally consistent set of units for various physical quantities. Recognising and correctly applying these units is fundamental in physics, as it ensures clear communication and accurate calculations. For instance, the SI unit for length is the metre (m), for mass it is the kilogram (kg), and for time it is the second (s). Many other units are derived from these base units, such as the unit for force (Newton, N), which is derived from mass, length, and time (kg m/s²).