Scalar and Vector

1 (a) Define the terms Scalar and Vector.

What is magnitude?

To understand the terms Scalar and Vector, you will have to first learn what the term Magnitude means. Magnitude can be defined as 'the degree or extent of something'. Sounds confusing? OK, here's an example. "Ali walked twenty miles that day." Now in this sentence, TWENTY is the magnitude of the distance Ali walked a specific day, for it tells us how much he walked that day, or as mentioned in the definition earlier, 'the extent of the distance he covered a specific day'.

Now here's a question for you to practice. "The temperature of the room was 20 degree Celsius". What is the magnitude of the quantity in this sentence?

Scalar

Hopefully, you have understood the meaning of magnitude. Now I'll come to Scalars. Simply put, a scalar quantity is 'a quantity that has a magnitude and a suitable unit only'. Examples include distance, time, mass, temperature etc. Now you might be thinking what do i mean by the word 'only'. By that, it means that scalar quantities do not have any direction.

Let's say, "Ahmad worked for 20 minutes". In this sentence, 20 is the magnitude, and minutes is the unit that represents time. Together, they represent time, which is a scalar quantity, as it does not have any direction.

Vector

 Vectors are quantities "that have a magnitude as well as a direction and a suitable unit". Examples include velocity, displacement, weight, acceleration, forces etc. Displacement is a vector because it is distance covered in a particular direction, e-g " Ali walked 20 km towards the east". In the example, 20 is the magnitude, km is the unit and East represents the direction of the quantity, therefore combining up to  represent displacement, which is a vector.  

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