In science, **motion** is defined as a change in position. An object’s position is its location.

**MOTION ALONG A STRAIGHT LINE**

If an object changes its position with respect to its surroundings with time, then it is called in motion. It is a change in position of an object over time. **Motion in a straight line** is nothing but Linear motion. As the name suggests, it’s in a particular straight line, thus it can be said that it uses only one dimension.

**Types of Motion**

In physics, motion can be classi ed under the following types for ease of understanding.

Linear motion – where the object moves along a straight line.

Circular motion – where the object moves along a circular path.

Oscillatory motion – where an object describes a repetitive to and fro movement retracing its original path.

Uniform motion – where an object travels equal distance in equal intervals of time.

Random motion – where the motion of the object does not fall in any of the above categories.

**Uniform and Non Uniform Motion**

** Uniform motion**

An object is said to be in uniform motion if it covers equal distances in equal intervals of time how so ever big or small these time intervals may be.

For example, suppose a car covers 60 km in first hour, another 60 km in second hour, and again 60 km in the third hour and so on. The motion of the car is uniform. Let us now understand the meaning of the words “how so ever small the time interval may be” used in the definition. In this example, the car travels a distance of 60 km in each hour. In the striker sense, the car should travel 30 km in each half an hour, 15 km in every 15 minutes, 10 km in every 10 minutes, 5 km in every 5 minutes and 1 km in every 1 minute. Only then the motion of the car can be said to be uniform.

** Non uniform motion**

An object is said to be in non uniform motion if it covers unequal distances in equal intervals of time.

Consider a bus starting from one stop. It proceeds slowly when it passes crowded area of the road. Suppose, it manages to travel merely 100 m in 5 minutes due to heavy traffic, when it gets out and the road is clear, it speeds up and is able to travel about 2 km in 5 minutes.

We say, the motion of the bus is non uniform i.e. it travels unequal distances in equal intervals of time.