Study of motion
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7.Average speed and instantaneous speed

The instantaneous speed of an object is not to be confused with the average speed.

Average speed is a measure of the total distance travelled in a given period of time; it is sometimes referred to as the distance per time ratio.

Suppose that during your trip to school, you travelled a distance of 10 km and the trip lasted 0.2 hours (12 minutes).
The average speed of your car could be determined as:


On the average, your car was moving with a speed of 50 kilometres per hour.

During your trip, there may have been times that you were stopped and other times that your speedometer was reading 65 km/h. Yet, on average, you were moving with a speed of 50 km/h.

If a moving object always moves at the same speed, moves with constant speed, the instantaneous and average speeds coincide. In this case the movement is uniform.

A

L

C