Speed

Distance covered per time taken.

A car travels along a road and leaks oil at the rate of one drop every second. The distance between the drops was measured and plotted on a graph.

The distance travelled between each drop is an indication of the speed of the vehicle. The faster the vehicle goes the greater the distance between the dots.

Notice how the speed of the vehicle is constant between 4 and 7 seconds at a speed of 5m/s. Every second it covers 5 metres. Between 7 and 8 seconds the speed is also constant at 3m/s. Every second it covers 3 metres. During the first 3 seconds of its journey the car is steadily increasing its speed. Notice how every second it covers more distance than during the previous second.

The distance covered by the vehicle per time is called the speed of the vehicle.

The units can be expressed as:
cm/s(centimetres per second);
m/s (metres per second);
Km/s(kilometres per second);
Km/hr(kilometres per hour) and so on.