Let us conduct a small activity to measure the speed of an object.
We are now going to measure the speed of a ball. Draw a straight line with the help of a chalk. Stand about 1 or 2 meters away from the line and roll the ball on the ground such that it is perpendicular to the line drawn. Record the time at the moment when the balls touches the line and also when it comes to rest.
The distance between the point where the ball crossed the line and the point where it came to rest has to be measured. Let different people repeat the same activity and record all the measurements. Calculate the speed in each case.
We can now compare the speed of various activities like walking or cycling with our friends. The speed of different animals can also be measured.
It is interesting to know that the satellites launched into the earth's orbit by the rockets obtain a speed of 8km/s while a tortoise can move only at a speed of 8cm/s.
Once we have the speed of an object we can find the distance moved in a given time by using the formula:
DISTANCE = SPEED X TIME
We can also find out the time that a particular object would take to cover a given distance at a certain speed using the following formula:
TIME = DISTANCE / SPEED
One must have observed a meter fixed on vehicles to measure the speed. Such a device is known as the speedometer.
There is also another device called the odometer which measures the distance moved by the vehicle.