Everything in this universe is driven by a natural desire to move and change its state. Inertia is the tendency of any object to resist the effect of external force to move. Surroundings are areas in their neighborhood where various objects are found. A body’s state of rest or motion is relative. A passenger sitting on a moving bus, for example, is at rest because he is not changing his position in relation to other passengers or objects on the bus. However, from the outside, the passengers and objects inside the bus appear to be moving. As a result, a body is said to be at rest if it does not change position relative to its surroundings. We live in a constantly moving universe. Atoms are constantly moving in every piece of matter. We move around the Earth’s surface, while the Earth orbits the Sun. The sun and the stars are also moving. In the world of mechanics, there are various types of motion based on different parameters, which are discussed here.
Motion is defined as a body’s free movement with respect to time, or if an object is changing its position with respect to a specific reference. When a body’s position does not change over time, we say it is at rest. Motion can be defined as a moving fan, dust falling from the carpet, water flowing from the faucet, a ball rolling around or a moving car. The universe itself is constantly in motion. The movement of air into and out of our lungs is another example of motion. Vehicles that transport passengers from their point of origin to their destination are in motion. Passengers’ positions are switched from one location to another in this case.
Are these all the same motions? Is the motion of a pendulum the same as that of a moving car or train? There are many different types of motion that occur around us and they can be classified based on time, speed, distance and path during motion.
Types of motion
Motion is classified into following types according to the state of motion.
Uniform motion: A body is said to be in uniform motion if it travels equal distances in equal time intervals. The time distance graph for such motion is a straight line. A car moving on a straight road at a constant speed, a flying aero plane at a constant height are common examples of uniform motion.
Non-uniform motion: A body exhibits non-uniform motion when it travels unequal distances in equal time intervals. As an example, consider a freely falling body. A curved line represents the time-distance graph of a body with non-uniform motion. A man walking down the street, a freely falling body, a train moving at various speeds, and so on are all examples of non-uniform motion.
According to direction, motion is classified as:
- One-dimensional motion: It is defined as a particle moving in a straight line.
- Two-dimensional motion: A particle moving in a plane along a curved path has two-dimensional motion.
- Three-dimensional motion: A randomly moving particle in space has three-dimensional motion.
Taking time into consideration, motion has 2 types: periodic and non-periodic.
What is periodic motion?
Periodic motion is defined as a motion that repeats itself after equal intervals of time. Typically, the objects subjected to this motion are in a to and fro motion. A moving pendulum, the hands of a working clock and the earth rotating on its axis are all examples of periodic motion.
What is non periodic motion?
Non-periodic motion is defined as a motion that does not repeat itself at regular intervals or does not repeat itself at all. A car moving down the road, a bird gliding across the sky and children playing in a park are all examples of non-periodic motion. In everyday life, we see multiple types of motion, such as birds gliding across the sky (translational and non-periodic), the Earth rotating on its axis which is rotational and periodic.
Motion has two types according to path followed by the body: linear and circular motion.
What is linear motion?
Linear motion is defined as a body moving in a straight line with no deviation. An athlete running on a straight track in a park is an example of linear motion, as is a bullet shot from a pistol, which always moves in a straight line.
What is circular motion?
When an object moves in a circular path constantly, it is said to be in circular motion. The speed of the object should be constant in circular motion. A few examples of circular motion include the rotation of the earth on its axis, the movement of a bicycle or a car on a park’s circular track, the motion of the moon around the earth and so on.
Based on the distance travelled by object, motion has two types: rotational and translational.
What is rotational motion?
Rotational motion is defined as the type of motion that occurs when an object moves along its axis and each of its parts travel different distance in a given amount of time. As a result, if an object is rotating, each of its parts will move a different distance in the same amount of time. For example, fan blades, windmill blades and so on.
What is translational motion?
It is a type of motion in which all of an object’s parts travel the same distance in the same amount of time. For example, moving vehicles on the road, a child falling, a bird flying in the sky and so on. There are two types of translational motion: rectilinear motion and curvilinear motion.
What is rectilinear motion?
Rectilinear motion occurs when an object moves in a straight line under translational motion. For example, a car moving on a straight road or a train moving on a straight track.
What is curvilinear motion?
Curvilinear motion occurs when an object in translational motion moves along a curved path. A car turning and a stone thrown up in the air at an angle are two examples.
Other types of motion are vibratory and oscillatory motion.
What is vibratory motion?
Vibrational motion occurs when a body moves back and forth around its mean position. Vibratory motion is defined as any object that moves or swings back and forth, up and down, pulsates, spins or vibrates. Vibrational motion is demonstrated by swinging pendulums, swings and metronomes.
What is oscillatory motion?
Oscillatory motion is defined as repeated motion, in which an object repeatedly performs the same movement. In the absence of friction, the oscillatory motion would continue indefinitely; however, in practice, the system eventually settles into equilibrium. Clocks, tuning forks, springs, swing motion and rotary bees are some examples.