Hint: We have seen the motion of a pendulum in various experiments. It undergoes to and fro motion which repeats itself. This kind of motion where the motion repeats itself after each equal interval of time is known as a periodic motion.
Complete step by step solution:
Let us see what it means by periodic motion. We all understand what a motion is. Different bodies travel in different kinds of motion.
One of the many sorts of motion is rectilinear motion or straight-line motion. From the word, straight line we know that it is a motion of a body traveling in a straight line. It can either be a uniform motion or a non-uniform motion which is dependent on the aspects affecting its motion.
When a body travels in a circular path, then its motion is called circular motion. When the body is moving with constant speed i.e. distance traveled by the body in unit time, then its motion is said to be in a uniform circular motion.
Occasionally, the motion of a body repeats itself. For example, the motion of a pendulum. If we can notice the motion of a pendulum, we can recognize that it's to and fro motion recurs. This kind of motion where the motion repeats itself after every same interval of time is called a periodic motion. The motion of a swing is similar to that of a pendulum. But the motion of a pendulum is periodic. So, the motion of a swing is also periodic.
Note:
In periodic motion, there are different types of motion. The back and forth motion of anybody like the pendulum is also known as oscillatory motion. One back and forth motion is said to be one complete cycle or oscillation. In an oscillatory motion, the acceleration of the body is proportional to the displacement of the body from its mean position, this motion is called simple harmonic motion.
