Concept of Scalar Quantity and Vector Quantity Physics

Mathematics is the language of Physics and often mathematical quantities are used to define the phenomenons of Physics. Speed, Force, Work, Velocity are the examples of few of these quantities. 

These quantities are categories into two part, scalar quantity and vector quantity based on the definition. Scalar quantity is defined as quantity which only has magnitude in its value such as mass, area and time. On the other hand, vector quantity is the quantity which has magnitude as well as direction in it. For example acceleration, velocity and force. 

Let’s try to learn about both scalar and vector quantity in much more detail.

What is scalar quantity ?

Scalar quantity is the physical quantity which only has magnitude and no direction. Magnitude means the physical quantity just has some value. For example, let’s say the mass of a bowling ball is 10 Kg. In this case, “10” is the magnitude and physical quantity is “Mass“. 

So scalar quantity only has the mass but these physical quantity does not have any direction which means they don’t define any direction the object is moving or is stationery. It’s just the value. 

The addition of this scalar quantity can be done by simple rules of algebra as there is no direction involved in it. 

Examples of scalar quantity: 

Some examples of scalar quantities are: 

1. Mass
2. Distance
3. Area
4. Speed
5. Temperature
6. Time
7. Volume

What is vector quantity ?

Vector quantity is the physical quantity which has both magnitude as well a direction. A vector is represented by the symbol “ ^ ” on the unit vector. Unit vector is the vector which has magnitude equal to one

To understand the concept of vector quantity in much more detail, lets take an example of a bike which is moving towards south with the velocity 80 km/h. 

As there is direction involved in it, we won’t use the word “speed” but instead velocity. In this case, the physical quantity velocity has both magnitude (80 Km/h) and direction (south).  So this is the vector quantity. 

Examples of vector quantity: 

Some examples of vector quantities are: 

1. Acceleration
2. Displacement 
3. Force
4. Electric Field
5. Velocity 
6. Momentum 

Difference between scalar and vector quantity:

Understanding the difference between the scalar quantity and vector quantity is important to get the basics clear. Here are the differences between the Scalar and Vector quantity: 

Scalar QuantityVector Quantity
1. Has only Magnitude and no direction.Has both Magnitude as well as direction.
2. Represented with a number (Magnitude) and unit.Represented with a number (Magnitude), direction using arrow at the top of the unit.
3. Only quantity symbol.Quantity symbol in bold with arrow on the top.
4. Examples: Speed and Mass.Examples: Velocity and Acceleration.

 

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