Motion and forces Study Guide

The acceleration due to gravity, represented by 'g', is the rate at which objects increase their speed as they fall freely near the Earth's surface. Its value is approximately 10 metres per second squared (10 m/s²). Being able to recall this value helps you compare and estimate the strength of acceleration in everyday situations, such as a car speeding up, a runner starting a sprint, or a rocket launch. This comparison allows you to judge whether those accelerations are greater than, less than, or about the same as g, deepening your understanding of motion in real-life contexts.

Speed is a measure of how fast an object is moving, calculated as the distance travelled per unit of time. Different objects and phenomena have characteristic speeds that are useful to recall for comparison and problem-solving. For instance, the speed of sound is significantly faster than typical human movement, while wind speeds can vary greatly but are generally much lower than the speed of light. Knowing these typical values helps develop an intuitive understanding of scale in physics and everyday situations.