The speed of an object is defined as
Distance travelled per unit time
Speed is a scalar quantity
This is because it only contains a magnitude (without a direction)
For objects that are moving at a constant speed, the equation for calculating speed is:
v = speed measured in metre per second (m/s)
s= distance travelled , measured in metres
t = time , measured in seconds (s)
Average speed
The speed of an object can vary throughout its journey
Therefore, it is often more useful to know an object's average speed
The equation for calculating the average speed of an object is:
A person starts from his office at 6:00pm and travels to his house which is 140km away. The person travels at a speed of 50km/hr till 7:00pm. After that he travels at a speed of 25m/s. At what time does the person reach his house?