Motion and forces Study Guide

Momentum is a fundamental concept in physics that describes the 'quantity of motion' an object possesses. It is a vector quantity, meaning it has both magnitude and direction. The magnitude of an object's momentum is directly proportional to its mass and its velocity. A heavier object moving at the same speed as a lighter object will have greater momentum, and an object moving faster will have greater momentum than the same object moving slower. The unit for momentum is kilogram metre per second (kg m/s).

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.