Distance & Displacement | Differences

Parameters of Motion-

 

The motion of a body may be described through the following parameters-

 

 

1. Distance
2. Displacement
3. Speed
4. Velocity
5. Acceleration
6. Jerk

 

In this article, we will discuss about distance and displacement.

 

Distance-

 

It is the total length of the actual path traveled by a body between its initial and final positions.

 

Characteristics of Distance-

 

• The SI unit of distance is meter (m).
• It has only magnitude and no direction. Hence, it is a scalar quantity.
• It can never be negative. It is always positive or zero.

 

Displacement-

 

It is the shortest distance measured in the direction from initial position to the final position.

 

Characteristics of Displacement-

 

• The SI unit of displacement is meter (m).
• It has both magnitude and direction. Hence, it is a vector quantity.
• It may be positive, negative or zero.

 

Example of Distance & Displacement-

 

Consider four cities A, B, C and D located as shown-

 

 

A salesman starts from city A, goes to city B, then to city C and then to city D. Then,

 

Distance traveled by the salesman

= Length of the actual path covered

= AB + BC + CD

= 20 km + 30 km + 20 km

= 70 km

 

Magnitude of displacement of the salesman

= Shortest distance between the initial and final position

= Shortest distance between city A and city D

= 30 km

 

Important Notes-

 

Note-01:

 

• The distance traveled by a body is always greater than or equal to the magnitude of displacement.
• The distance and displacement are same when body moves along a straight line path without taking any turn.

 

In general,

 

Note-02:

 

The displacement of the body is always zero if it returns back to its initial position.

 

Note-03:

 

The displacement of a body is independent of the choice of the origin of the position coordinates.

 

Differences Between Distance & Displacement-

 

The following table shows the differences between distance and displacement-

 

Distance	Displacement
It is the total length of the actual path traveled by a body between its initial and final positions.	It is the shortest distance measured in the direction from initial position to the final position.
It is a scalar quantity.	It is a vector quantity.
The distance covered by a body depends on the path followed by the body.	The displacement covered by a body does not depend on the path followed by the body.
Distance can never decrease with time.	Displacement may decrease with time.
It can never be negative. It is always positive or zero.	It may be positive, negative or zero.
There is always a distance covered whenever there is a motion.	There may be no displacement even when the body has moved. It is possible when body comes back to its initial position.
It is always greater than or equal to the magnitude of displacement.	It is always less than or equal to the distance covered.

 

Read the next article on-

Speed & Velocity

 

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