Types of Motion

Everything in this world is naturally in a continuous state of movement. Specifically, the Earth seems to be in a stable state; however, it is also somewhat in a motion state. That makes it clear that everything present on Earth is also in motion. Even though we don't experience particular objects' movement, they are in motion concerning something or someone.

Typically, we notice that different objects move in different ways. Therefore, there are different types of motion primarily based on the nature of the movement. In this article, we are discussing all the common types of motion and their definitions. Before we discuss various motion types, let us first briefly understand the definition of motion, including the related terms used to define motion.

What is a Motion?

Motion is defined as the change in an object's position with respect to time. Technically, each object in this universe is in motion. Even the universe itself is in continual motion. The motion can be slow or fast, but there will a motion always. However, when an object is at rest (not moving), we call it stationary.

When we say that the object is in motion, it is always said concerning any other object. For instance, when we see a person walking on the road, we say that a person is in motion. In this case, the person is generally moving with respect to stationary objects such as trees, poles, etc. Besides, when we see a person sleeping on the bed, we say a person is in a rest state (not in motion). It is because the person is stationary with respect to the bed or some other objects around him. But as we know that the Earth is in motion, and so technically, everything is in motion. The examples explained here also clarify that the same object can be at rest and in motion in different states or times.

Motion is mainly defined using the following terms:

• Distance: The total measured length of the path traveled by the object
• Displacement: The shortest difference between the initial position and final position of the moving object
• Speed: A rate at which the position of the object changes with respect to the origin and the time
• Time: Total duration of period the object is traveling (moving)

All these quantities help in describing the change in the position of objects between particular points.

Some General Examples of Motion

The following are some general life examples of motion, which will help us to understand motion clearly:

• Humans' regular activities, such as running, walking, jumping, and many others, include motion with them. All these activities change the state of the human body.
• When we breathe, there is a flow of air that goes in and out of our lungs. This flow of air is also an example of the motion of air particles.
• The movement of vehicles is also an example of motion.
• Birds flying in the sky are also in motion.

There are various other everyday-life examples of motion. Let us now understand the different types of motion, which will help us distinguish the motion types in different categories.

Types of Motion

Different particles usually have different movement styles. Sometimes, the same particle may follow different styles. For instance, an object may move in a straight path, circular path, or follow any other random path. According to the different paths or ways of movements, the motion is classified into the different type, such as:

• Linear Motion
• Rotary Motion
• Oscillatory Motion
• Periodic Motion

What is Linear Motion?

Motion is linear when all the parts of an object move from one place to another at a particular time. It is important to note that if an object moves along the perfectly circular path, an object's motion is not linear. A linear motion has many significant applications in the field of robotic, automation, manufacturing, etc.

The high use of this type of motion is seen in linear actuators. Some common examples of linear motion include the followings:

• The motion of the train on a track
• The motion of vehicles on a road
• The motion of a falling apple from a tree, etc.

Linear motion is further classified into the following two types:

Rectilinear Motion

When an object in linear motion moves towards a straight line's path, an object's motion is called a rectilinear motion. A vehicle moving on a straight road and a train moving on a straight-line track are few examples of rectilinear motion.

Curvilinear Motion

When an object in linear motion moves along the curved path, an object's motion is called a curvilinear motion. A vehicle taking a turn and an object threw up at any angle are few examples of curvilinear motion.

What is Rotatory Motion?

The rotatory motion refers to a type of motion in which different particles of an object move in a circular path and travel different distances at any specific time intervals. In a rotatory motion, the object typically moves or rotates on its axis. It is also sometimes referred to as the rotational motion and rotary motion.

Like linear actuators, rotary actuators are also widespread and can be seen in electric, hydraulic, and pneumatic options. The Earth is constantly rotating on its axis around the sun is the best general-life example of rotatory motion. Other common examples include the followings:

• A rotating fan
• A steering wheel of the car
• A swinging of wheels in vehicles around its axis

What is Oscillatory Motion?

An oscillatory motion refers to a type of motion in which an object moves or oscillates around its mean position. This means that the object repeats the cycle of motion around its mean position. More specifically, it is the motion of an object that moves like it is doing front and back oscillation repeatedly at certain time intervals. The oscillatory motion is sometimes also known as oscillating motion. The movement of an object is termed oscillations.

The motion of a pendulum of a wall clock is the best example of an oscillatory motion. In particular, a pendulum repeats its motion at a specific period without actually displacing it from its position. Although it is somewhat stationary, it is in oscillatory motion. Some other common examples of this type of motion include the followings:

• A table fan or a wall-fan swinging around different directions (left and right) to release the air is the form of an oscillatory motion.
• When a child on a single swing is pushed, the swing moves to and fro about its mean position, making an oscillatory motion.
• Both linear actuators and rotatory actuators have oscillatory motion.
• The sound waves travel in oscillatory motion.
• The strings on guitars or sitars move to and fro around their mean position when they are strummed. The movement of strings is an oscillatory motion.

What is Periodic Motion?

A periodic motion refers to a type of motion in objects that typically repeats itself at equal time intervals. Some examples of objects undergoing periodic motion include the bouncing ball, a moving swing, water waves, a rocking chair, etc.

Apart from this, motions that do not repeat are called non-periodic or may fall under other motion types. For instance, the birds gliding across the sky where birds' motion is non-periodic and may usually fall under the linear motion category.

Examples that may have more than one type of motion

There is nothing wrong with an object having more than one type of motion. It is possible. Let us look at some examples and understand how this can be possible:

• The Earth: The Earth rotates on its axis, and this is why it has rotational motion. The Earth also repeats its motion around the sun in a circular path at particular intervals (one year). Therefore, it also has periodic motion. Technically, the Earth is having two different types of motion at the same time.
• Ceiling Fan: If we consider an entire ceiling fan as a whole when it is on, then it has a rotational motion as it rotates on its axis. Besides, when we consider the outer parts (blades), then blades are in periodic motion as they keep following the same circular path at regular intervals.
• Bicycle: Consider a bicycle that is moving on a straight road. In this case, the wheels of a bicycle rotate around their axis, so there is a rotational motion. Furthermore, the bicycle is moving forward on a straight road, so there is also a rectilinear motion.
• Sewing Machine: The sewing machine includes a wheel that rotates around its axis. The motion of the sewing machine is the rotational motion. Moreover, the needle continually moves up and down when we operate the sewing machine. The needle of the sewing machine has a periodic motion. Therefore, the sewing machine has two different types of motion such as the rotational and periodic motion.

Some other Classifications of Motion

Apart from the types mentioned above, we can also distinguish motions according to directions and the state of motion:

Classification of Motion According to Directions

There are mainly three types of motion depending on the directions, such as:

• One Dimensional Motion: When the object moves along a straight line, an object's motion is known as the one-dimensional motion.
• Two Dimensional Motion: When an object moves along a curved path in a plane, an object's motion is known as the two-dimensional (2-D) motion.
• Three Dimensional Motion: When an object moves randomly in space, an object's motion is known as the three-dimensional (3-D) motion.

Classifications of Motion According to State

There are mainly two types of motion depending on the state of motion, such as:

• Uniform Motion: When an object is in motion and travels the equal distance in equal time-periods, the graph drawn between the time and distance is a straight line. This type of motion of an object is called a uniform motion-for example, the Earth's rotation and revolution.
• Non-Uniform Motion: When an object is in motion and travels the unequal distance in equal time-periods, then an object's motion is known as the non-uniform motion. In non-uniform motion, the graph drawn between the time and distance is usually a curved line. It is also known as an accelerated motion-for example, a freely falling object.