Types of Motion: Introduction

Introduction

Everything that we see around us is in the condition of continuous movement. There is a motion that is witnessed in every basic part of the world. But how do we define this movement? Are there different types and classifications of the same? When considering the change in position, two important factors come into play, which is distance and displacement. Hence, motion can be defined as the change in the position of an object when compared to time. It is applied to various physical systems, objects, matters, molecules, atoms, the space-time quantum, etc. It helps signify that there is a continuous change in the positions of any physical system in the space.

This article explains what motion is and the classification of motion into four major types along with frequently asked questions.

WHAT IS MOTION?

Motion is defined as the change in the position of an object when compared to time. Let’s say a book falls off the table, water is flowing from a tap, and even the air that we breathe is considered to be motion. Everything in the world moves. Motion is an important topic in the subject matter of physics. This matter is usually described in the terms of distance, displacement, time, and speed. Out of these four, distance and displacement are used to explain the change in the position through motion.

Let’s take an example, suppose the distance between two given points A and B is ‘d’. An individual travels from point A to point B and comes back. How would we calculate the distance traveled and the displacement?

The formula would be, distance traveled = the total path that is covered = d+d = 2d

The displacement that is measured is said to be the shortest distance between the initial position and the final position. In the example above, both are the same, which is why the displacement is considered to be zero.

Types of Motion

Different types of motion can be seen in any object. There are four types of motion which have different mechanical meanings. These are – Rotary motion, Linear motion, Oscillating motion, and periodic motion.

Rotary Motion

This type of motion exists when the object is traveling in a circle, it usually occurs when the object is rotating around its place or axis. This was the first type of motion that was invented in primitive times by scientists studying motion. When we look at a three-dimensional object, it may have an infinite rotation axis. An example of a rotary motion is the movement of wheels and also the steering wheel of a car when driving. It is the same thing that happens with the engine of a car as it moves in the same place.

Linear Motion

In this type of motion, the object moves either in a straight line or in a curved path. The classification of this type of path in linear motion is –

• Rectilinear motion – The object here moves in a straight line.
• Curvilinear motion – The path is curved in this case.

The best example of such a type of motion is the linear actuators where we can find cars, cycles, etc. traveling in a straight line. This type of motion has a lot of importance in the world of automation, robotics, and manufacturing.

Oscillatory Motion 

The movement that occurs in this type of motion is the front and back movement or rather oscillation that takes place. It is described as the movement of an object around its mean position. If the object is repeating its cycle of motion after a particular period, then it is called oscillating motion.

A pendulum clock can be considered to be a very good example of an oscillating motion. As it can be seen that it repeats its motion at intervals. A few other examples of oscillatory motion are a child swinging in a to and fro motion on a swing, a table fan spinning, also the cords of a guitar.

Periodic Motion

The periodic motion is a type of motion that is repeated at equal intervals of time. A few examples of this type of motion are a bouncing ball, swings in the park, rocking chairs, the vibration of a tuning fork, etc. The more important examples of the same are the rotation of the earth, in its orbit around the sun.

Vibratory Motion

Vibration is a very mechanical phenomenon where the oscillations occur only at an equilibrium point. These may be periodic like the movement of a pendulum or at random, which is unpredictable, as the movement of a tire on any road. Some vibrations are desirable and undesirable. The desirable vibrations are considered to be motions like the tuning fork, a mobile phone vibrating, a harmonica being played or the loudspeaker. A vibration, however, can also be undesirable, when it is considered to waste energy and create disturbing sounds. Examples of this are, any mechanical device making an unwanted sound, or the vibrations of an engine.

Random Motion

Random motion is the type of motion that is unpredictable and the object is likely to move in any direction. An example of this type of motion is the movement of gaseous molecules. The movement of these molecules is random and they are continuously moving around in random directions.

Examples of Motion

The most common examples of motion that can be witnessed in our everyday lives are activities like running, walking, cooking, where there is a change in the position of the object when we indulge in these activities. Something as simple as breathing, the flow of the air in and out of our lungs is also considered to be an example of motion.