Unit of Displacement

What Is Unit of Displacement?

The shortest distance between the initial and final point is considered as displacement. Displacement always takes place in a straight line between the initial and final positions of the objects or body. The displacement is a vector quantity which means that it contains both magnitude and direction. Displacement is a one-dimensional quantity. We can also find the displacement of one object with respect to another object, which is known as the relative motion of the position of the object. As the displacement is a quantity to measure, we need a unit. The unit is referred to as the standard measure quantity. The unit of displacement is measured in meter or centimeter. There are two ways in which units of the object can be written that are discussed below.

S.I Unit of Displacement

The word S.I stands for System International. Under the system international, a few physical quantities are named and accepted internationally. The short form of the system international units is MKS which means “meter, kilogram, and second”. The unit of displacement is a meter in S.I system as displacement simply means length covered. S.I unit is further divided into two parts that are base units and derived units. The unit of displacement comes under the category of base units. The displacement is measured in terms of meter. Displacement is related to the length. As length is the fundamental quantity that is measured in meter. Meter is the S.I unit of displacement.

CGS Unit of Displacement

The full-form of CGS is centimeter-gram-second. In this type of unit, the unit of physical quantities are measured in centimeter, grams. Here in this type length is measured in centimeter, mass is measured in grams. However, the only quantity that remains the same is a time which is measured in second as same in the S.I system. 


There are two types of CGS system that are base units and derived units. In the base, units came centimeter, grams, and second. But in the derived unit, there are different physical quantities like velocity whose unit is derived from its formula that is centimeter/second, there are a lot of physical quantities which are under this system.


The CGS unit of displacement is a centimeter, which means the length covered is measured in centimeter. As we know that in S.I system displacement is measured in meter and in conversion to the CGS system it will become centimeter. During the conversion of meter to a centimeter or vice- versa, 1 meter is equal to 100 centimeter that is 1 m=100 cm or 1 cm =0.01 m. If we take 4 meters and convert into conversion centimeter it becomes 400 cm.

Fun Facts

  1. Earlier there was only the discovery of CGS units that are used in mechanics and electromagnetism which are branches of physics. In this, only a 3-dimensional system is used. Further discovery leads to the creation of the S.I system, which is now used in mechanics and electromagnetism with a 4-dimensional system.

  2. In daily life, experimental physics and the engineering concepts of physics claims more use of S.I units in electromagnetism, CGS system is not that much applicable in it.

Examples of SI Unit Displacement

  1. The conversion of the S.I system into a CGS system is possible, for example,  velocity in S.I system can be written as meter/second in the CGS system it can be written as centimeter/ second.

  2. The diameter of proton in the CGS system is 0.00000000000017 but in S.I system it is 0.000000000000000017.

  3. The unit of force in the CGS system is dyne whereas in the S.I system the unit of force is the newton.

  4. One meter is taken to measure the distance light traveled in 1/299792458 of the second in a vacuum.

FAQ (Frequently Asked Questions)

1. Discuss the reason behind displacement can be negative and zero?

Displacement can be negative but it cannot be negative always. Displacement is negative due to its vector quantity as it contains direction and magnitude. When the magnitude of the body or object remains the same but travels in the opposite direction which gave negative displacement. If the direction remains the same for the objects then it will be a positive displacement. The reason behind zero displacements is that when the object starts from an initial position and comes back to the initial position after the round trip, in that case, there are zero displacements.

2. How distance is different from displacement?

The distance is a vector quantity whereas the distance is a scalar quantity. The meaning of distance is how much ground has been covered by the object. Whereas the displacement means the shortest distance covered by the object. The displacement is along a straight line whereas in distance it is not necessary to be a straight line. The unit of both the distance and displacement are the same in both the measuring system. Another important difference is that distance cannot be zero but displacement can be zero. For example, the round trip in case of displacement is zero because it depends upon the shortest distance between the initial and final position as in the case of the round trip the object came back to its initial position therefore displacement can be zero.