Introduction to Speed

Speed is the rate of motion, or equivalently the rate of change of distance. Uniform speed is a speed which is constant throughout the whole process of something. To find average speed, first find the distance travelled and the time taken to travel this distance. Following, divide the distance travelled by the time taken and you will get the average speed. For example,
John is driving a car at 50km/h for 1 hour and 80km/h for 30 minutes, what is his average speed?
Distance travelled = 50km + 80/2 km
= 50km + 40km
= 90km
Time Taken = 1 hour and 30 minutes
Average speed = 90km/90minutes x 60 minutes
= 60km/h
Remember the unit is km/h, not over 10 or 30 minutes. Time may be used together with speed. Average speed is very practical if you are planning to travel to somewhere in a period of time.