Question

What is meant by rectilinear motion? Give two examples of rectilinear motion?

Answer 1

Hint: Rectilinear motion can be described by the number of dimensions used to describe the motion. Both scalars as well as vectors can be used to define it. It is the simplest form of motion and can be divided into two types based on the rate of change of position of the body undergoing rectilinear motion.

Complete answer:
Rectilinear motion is the motion of a body travelling in a straight line. It is also known as the motion in one direction or linear motion.
Graphically, only one dimension is involved in rectilinear motion, or the change of position of a body along one dimension only is rectilinear motion.
In order to define motion in a straight line, both scalar and vector quantities are used. Distance or displacement is used to define the position, velocity or speed is used to define rate of change in position while acceleration is used to define the rate of change in velocity.
Linear motion can be of two types; constant or uniform motion and non-uniform motion.
In uniform motion, the velocity of a body in rectilinear motion remains constant while in non-uniform motion, the velocity changes continuously.
Therefore, the rectilinear motion is the motion of a body in a straight line.

Note:
When a body is moving in a straight line in space, then more than one dimension is used to define its motion. The other type of motion is; rotational motion. It is the motion in which a body moves in a circle about an axis of rotation. All quantities used to define rotational motion are analogous to rectilinear motion.