Question

What is rotatory motion? Give two examples.

Answer 1

Hint:The motion of an object is described by the path it takes or the direction in which it moves. The path can be linear, circular, curvilinear, oscillatory or completely random. The rotatory motion refers to the circular motion of an object.

Complete step by step answer.
Step 1: Try to explain the circular motion of a particle about its own axis of rotation.
The circular motion of an object about an imaginary axis is referred to as rotatory motion. Every object that executes rotatory motion has its own axis of rotation. In rotatory motion, the radius of the circular path described by the rotatory object will remain constant.

Step 2: Mention two common instances of rotatory motion.
Two instances in our everyday life where we see a rotatory motion is when we see the motion of the blades of a ceiling fan. The rotating blades describe a circular path and at no point of their motion does the radius of this circle change. These blades rotate about a fixed axis.

Another instance of rotatory motion is the movement of the wheel of a bicycle. As the person pedals the bicycle, the wheel rotates about an axis and just like the blades in the ceiling fan, the wheel does not change the radius of its circular path.

Note:As the object is moving along a circular path, its equation of motion will be similar to the equation of a circle. At each point along the circular path, the direction of the rotatory object will also change. The blades of the ceiling fan rotate about a vertical axis while the wheel rotates about a horizontal axis. In the case of the rotating wheels, there is also translational motion.