The free movement of an object in relation to time is known as motion. It can be described as the act of shifting one’s position. For instance, a moving train, a rotating fan, a rolling ball, and so forth. Even though the planet is always in motion, there are several sorts of motion that will help you grasp things more thoroughly.
What is Motion?
The motion of an object is categorized into four, on the basis of the nature of the movement of the object as,
 Rotatory Motion – It is a type of motion in which an object rotates around a central axis. Consider the case of a revolving fan.
 Oscillatory Motion – In oscillatory motion, an object moves back and forth in the same motion. Consider the pendulum.
 Linear Motion – This is a onedimensional motion that occurs in a straight line. for example, a train on a track.
 Reciprocating motion – A continuous upanddown or backandforth motion is referred to as a reciprocating motion. A gymnast, for example, swinging on a ring.
However, on the basis of the path followed by the object, the motion is described in two ways:
 Rectilinear Motion – A straightline path of motion. All particles in this motion go the same distance in a parallel straight line.
 Curvilinear Motion – A curved line path of motion. The body’s orientation in space remains constant, but the trajectories of individual particles are curved.
What is Linear Motion?
Linear motion is defined as when a body is moving in a straight line or along a curved line in a plane. It can be along any curve line or path.
Examples of Linear Motion:
 Athletes running along the straight line.
 Skating or swimming done by any person possesses linear motion.Â
Types of Linear Motion
 Uniform Motion – When a body moves in a straight path at a consistent speed, it is said to be in uniform motion. For example, consider an automobile driving at a constant pace down a straight route. A straight line can be used to indicate uniform motion in a graphical representation.
 NonUniform Motion – When a body travels the same distance in the same amount of time, it is said to be in nonuniform motion. This motion can be depicted as a curved line in the pictorial form.
What is Rectilinear Motion?
Rectilinear motion is defined as a phenomenon in which a body is moving only along a straight line. It is one type of linear motion.
Examples of Rectilinear Motion
 Falling of objects from a certain height.
 Ants moving in a straight line.
 Moving of train on track.Â
 Falling of stone from the top of the building to reach the ground.
Difference between Linear Motion and Rectilinear Motion:
Linear Motion 
Rectilinear Motion 
Linear motion is defined as when a body is moving in a straight line or along a curved line in a plane.  Rectilinear motion is defined as a phenomenon in which a body is moving only along a straight line.Â 
Examples of Linear Motion are,

Examples of Rectilinear Motion are,

It is along any curve line or straight line in a plane.  It is only along a straight line in a plane. 
In this the direction of the motion changes.  In this, the direction of motion remains the same. 
It has nonzero acceleration.  It has zero acceleration. 
It is also called translation motion.  It is one type of linear motion. 
It is a onedimensional motion in a straight line.  It is a twodimensional motion in a plane. 
There are two types of linear motion.

There are three types of Rectilinear Motion.

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Sample Questions
Question 1: What are the two types of linear motion?
Answer:
Linear motions is of two types, they are
 Rectilinear motion.
 Curvilinear motion.
RectiIinear Motion:
Rectilinear motion is defined as a phenomenon in which a body is moving only along a straight line. It is one type of linear motion.
Example:
 Falling of objects from certain height.
Curvilinear Motion:
Curvilinear motion is defined as the motion of the l objects moving in a circular path.
Example:Â
 Motion of earth around the sun.
Question 2: Does motion have any units.
Answer:
No Â motion does not have any units, because motion is not a physical quantity and thus it cannot be measured. So it does not have any units.
Question 3: A man is moving in a car with a velocity of 8 m/s, then he suddenly stops the car. Does he brake to stop completely with an acceleration of 4m/s^{2}?
Answer:
Given that,
Initial velocity u = 8m/s
Final velocity v = 0 m/s
Acceleration a = – 4m/s^{2}
From kinematics formula,
v^{2 }= u^{2 }+ 2ad
0^{2} = 8^{2} + 2 Ã— (4) Ã— d
64 – 8d = 0
8d = 64
d = 64/8
= 2 m
Therefore, the distance travelled by man in car is 2 m.Â
Question 4: A ball is moving with a velocity of 19 m/s for a distance of 120 m. Find the time taken to reach that distance?
Answer:
Given that,
Initial velocity u = 10 m/s
Final velocity v= Â 0 m/s
distance travelled d = 120 m
From equation of motion,
d = (v + u)t/2
120 = (0 + 10)t/2
120 Ã— 2 = 10t
240 = 10t
t = 240/10
= 24 s
Therefore the time taken to reach that distance is 24 s.
Question 5: A car is moving at 20m/s speed up to 60 m/s in 8 sec. Find the acceleration of the car?
Answer:
Given that,
Initial velocity u = 20 m/s
Final velocity v= Â 60 m/s
Time t = 8 sec
From equation of motion,
v = u + at
60 = 20 + a Ã— 8
60 – 20 = 8a
8a = 40
a = 40/8
a= 5 m/s^{2}.
Therefore, the acceleration of the car is 5 m/s^{2}.
Question 6: An object is thrown from a building with a constant acceleration of 20m/s^{2}. Find the speed after 5 sec when it was dropped.
Answer:
Given that,
Initial velocity u = m/s
acceleration a = 20m/s^{2}.
Time t = 5 sec
From equation of motion,
v = u + at
v = 0 + 20 Ã— 5
v = 100m/s.
Therefore, the speed after 5 sec is 100 m/s.
Rectilinear motion and Linear Motion – FAQs
What is the main difference between rectilinear motion and linear motion?
Rectilinear motion refers specifically to motion along a straight path, while linear motion is a broader term that encompasses motion in any direction, including both straight paths and curved paths.
Can linear motion be rectilinear?
Yes, linear motion can be rectilinear if the motion occurs along a straight line. However, linear motion can also include motion along curved paths, which would not be considered rectilinear.
Can rectilinear motion be linear?
Yes, rectilinear motion is a type of linear motion because it occurs in a straight line. However, not all linear motion is rectilinear, as linear motion can also include motion along curved paths.
What are some examples of rectilinear motion that are not linear motion?
Examples of rectilinear motion that are not linear motion include motion along a straight line on a curved surface, such as a roller coaster track, or motion along a straight line that is part of a larger curved path.
What are some examples of linear motion that are not rectilinear motion?
Examples of linear motion that are not rectilinear motion include motion along curved paths, such as the orbit of a satellite around the Earth, or motion along a circular track.
How can one distinguish between rectilinear motion and linear motion in practical scenarios?
Rectilinear motion is characterized by motion along a straight path, whereas linear motion can include motion along both straight paths and curved paths. Observing the path of motion can help differentiate between the two.
Do the equations governing rectilinear motion differ from those governing linear motion?
The equations governing rectilinear motion are essentially the same as those governing linear motion because rectilinear motion is a subset of linear motion. Both types of motion involve concepts such as displacement, velocity, and acceleration, which are described using similar equations.