Question

What are the differences between linear motion and circular motion?

Answer 1

Definition of motion:

The change in position of an object with respect to its surroundings in a given interval of time is called motion.

Linear motion

1. Linear motion is also called rectilinear motion. It is a motion on a straight line in one dimension.
2. When the object travels along a straight line it changes its position along with time.

Circular motion

1. Circular motion is an object’s moving across a circle or movement across a circular direction.
2. It has a rotation around a fixed axis of the object which is three-dimensional and it involves circular motion of all its parts.

Difference between linear motion and circular motion:

Linear motion	Circular motion
1. The motion of a body in a straight line path with constant velocity.	1. The motion of an item in a circle with a constant radius and angular velocity.
2. The direction of motion doesn’t change. The direction is the same throughout the motion.	2. Radial acceleration is $\frac{{\mathrm{v}}^2}{\mathrm{r}}$ (centripetal acceleration) and directed towards the center.
3. Example: A car running on a straight road.	3. Example: Motion of earth around the sun.

Therefore, motion is the change with time of the position or orientation of a body.