Types of Motion - Part 2

Swinging in a garden is real fun .. isn't it ??

Can you say what kind of motion you are in when you are swinging ?

While swinging, you are neither moving in a straight line nor in a circle.

So, your motion is neither rectilinear nor circular. Then ?

If you see, on a swing, we repeat our motions after fixed intervals of time...

i.e. we travel through the same path after certain time intervals over and over again.

This type of motion called is called - "".

Where else can we see Periodic Motions ?

The motion of the pendulum in pendulum clocks is a great example of periodic motion, as you can clearly see that it repeats it's motion after a fixed interval of time.

Branches of trees also move to and fro repeating their motion. Thus, their motion can also be termed 'periodic'.

Strings of guitar or sitar when plucked, also displays 'periodic motion'.

You will be surprised to know, that even the revolution of Earth or any planet, is also periodic as they repeat their motion around the sun in fixed intervals of time.

Actually the motion of the Earth is a of few other kinds of motion - Can you name them ?

Motion of the Earth is a combination of Rotational motion around its axis + Circular motion around the Sun + Periodic motion.

Where else can we find such combination of motions ? Any guesses ?

Yes! A moving Ball. A ball when moving forward, moves in a straight line, as well as it rotates about its axis.

Thus, the ball undergoes rectilinear motion as well as rotational motion.

Similarly, in a sewing machine we can also observe a combination of motions.

The sewing machine, itself does not move - i.e. it remains at rest, whereas it's wheel undergoes Rotational motion.

The needle of the sewing machine again, moves to and fro periodically, which is nothing but a Periodic motion. Isn't it interesting !

Some times objects move so randomly, that their motion cannot be understood by any of the discussed types of motion.

For example,the motion of butterflies is neither circular, nor they move in straight line. Their motion is spontaneous and random.

Similarly, the motion of the kites are also random and its very hard to give it a particular name. So, we say such type of motion as .

Let us take a small REVISION

If an object repeats its motion after a fixed interval of time, it is said to be in Periodic Motion. Ex: Pendulum of a Pendulum clock.

Objects can also undergo - a combination of motions. Ex: Motion of Earth => Rotation + Circular + Periodic.

If the movement of an object is zig-zag and very random, then it's motion is called .

The End