Motion and Time
Motion is the change in the position of an object with respect to its surroundings. It is the distance moved by an object or its displacement.
The distance moved by an object in a unit time is called its speed. The speed of an object helps to compare whether a body is moving fast or slow. Speed of an object is the ratio of the distance travelled it to the time taken to cover the particular distance.
The time that a body takes to cover a particular distance is measured with the help of certain measuring instruments. All the time measuring instruments work on the principle of periodic motion. A simple pendulum represents a periodic motion. The to and fro motion performed by a simple pendulum is called oscillatory motion. The time taken by a pendulum to complete one oscillation is called its time period.
Odometer and speedometer record and compare the speed of different moving vehicles. A graph is used to represent a pictorial form of such records. Most commonly used graphs are bar graphs, pie charts and line graphs. Motion of an object is represented in a pictorial form by using a line graph called distance-time graph. It represents the change in the position of an object with respect to time.