Motion in a Straight Line

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.

The linear motion, also called the rectilinear Motion can be of two types –

· Uniform linear motion with constant velocity or zero acceleration

· Non-uniform linear motion with variable velocity or non-zero acceleration

Linear motion is the simplest kind of one-dimensional motion.

As Newton’s first law of motion suggests, the object will either be in rest or continue to move in a straight line with a uniform velocity unless and until an external force is applied to it.

Linear motion is a one dimensional motion but in general, motion has magnitude and direction both, i.e. an object’s position and velocity are described in vector quantities.

Uniform Motion in a Straight Line:

If a body travels in a straight line and covers equal amount of distance in an equal interval of time, then it is said to have uniform motion. In simple words, a body is said to have uniform acceleration if the rate of change of its velocity remains constant.

For example: if a car travels at a speed of 60 km/hour, than it will cover a distance of 1 km/minute. In this sense, the motion of car acceleration is uniform.

Non-uniform Motion in a Straight Line:

Unlike, the uniform acceleration, the body is said to have a non-uniform motion when the velocity of a body changes by unequal amounts in equal intervals of time. The rate of change of its velocity changes at different points of time during its movement.

For example: A boy kicking a football, might cover 4 meters in the first attempt, 6 meters in the second attempt, 9 meters in third attempt and so on as per the velocity exerted by the boy.