Speed does not involve direction. Speed is a scalar quantity. • The speed of a moving object is rarely constant. When people walk, run or travel in a car their speed is constantly changing. • The speed at which a person can walk, run or cycle depends on many factors including: age, terrain, fitness and distance travelled. Typical values may be taken as: walking ̃ 1.5 m/s, running ̃ 3 m/s, cycling ̃ 6 m/s. • Students should be able to recall typical values of speed for a person walking, running and cycling as well as the typical values of speed for different types of transportation systems. • It is not only moving objects that have varying speed. The speed of sound and the speed of the wind also vary. • A typical value for the speed of sound in air is 330 m/s. • Students should be able to make measurements of distance and time and then calculate speeds of objects. • For an object moving at constant speed the distance travelled in a specific time can be calculated using the equation: distance travelled = speed × time, s = v t. distance, s, in metres, m; speed, v, in metres per second, m/s; time, t, in seconds, s. • Students should be able to calculate average speed for non-uniform motion.