Question

How does rotatory motion different from circular motion?

Answer 1

In physics, a body is said to be in motion if it changes its position with respect to time. Both circular and rotatory motions are an example of motion where a reference axis is used to determine the trajectory of the motion of a given body.

Complete answer:
Let us first understand circular motion and rotatory motion. A motion is said to be in circular motion if it moves in a circular path with some an arbitrary radius and here, the radius of circular path doesn't change with time; it's a constant value. In circular motion, the direction of velocity always changes and its magnitude remains the same in uniform circular motion.

A rotatory motion is also said to be a rotational motion in which a body continuously rotates about an axis. But, the main difference between circular motion and rotatory motion is that in circular motion body rotates about a fixed axes which lies outside the body but in rotational motion, the axes of rotation of a body lies inside the body.In circular and the rotatory motions, the distance of the axes of rotation and a point on the body always remains fixed but it’s not fixed in curvilinear types of motion.

Note: Remember, rotation of earth and other planets around the sun is an example of circular motion where all planets revolve around the axis of sun but the rotation of earth and other planets about its own axis is an example of rotatory motion.