Scalar Quantities Vs Vector Quantities

Physics involves measuring and predicting various quantities (or physical values) like force. mass. and velocity.These values can be classified into those having only magnitude and those having both magnitude and direction. A quantity that has magnitude without a direc­ tion is referred to as a sea/or quantity. Mass is a scalar quantity. Energy and work are also scalar quantities.

On the other hand. force is a value with a direction. You can see that from the fact that the motion of an object changes if you apply force from a different direction.

A quantity that has a direction is called a vector. Velocity and acceleration and momentum are also vector quantities, as they have direction. You may forget the terms scalar and vector, but you should keep in mind that there are two types of values in physics:

1. Those with just a magnitude 
2. Those with both a magnitude and a direction

Vector: Basics

A vector is represented using an arrow.The length of the arrow represents the magnitude of the vector. and the point represents its orientation. or direction.Two vectors with the same magnitude and direction are equivalent to one another. even if they do not have the same origin.

 

Also note that the magnitude of a vector (represented by the length of the arrow) can be noted with absolute value symbols, like |a| or simply as a.

The sum of two vectors (a + b) is shown by joining the head of vector a to the tail of vector b. and then extending a line from the tail of a to the head of b, as shown in the figure. As this vector is a diagonal of the parallelogram in the figure, it is obvious that it is also equivalent to b + a. Therefore, we know that the following is true:  

Commmunitative Law: a + b = b + a

 

Negative Vector

Vector -a or a preceded by a minus sign, yields a sum of zero when added to Vector a. In an equation, the relationship looks like this: a + (-a) = 0

In terms of geometry, Vector -a is simply vector of the same magnitude as Vector a, but in the exact opposite direction. The 0 on the right side of this equation represents zero as a vector, referred to as a zero vector. When vectors cancel each other out in this way. an object is said to be in equilibrium.

 

Difference between Two Vectors

The difference between two vectors (a - b) can be defined as follows:

Commmunitative Law: a - b = a + (-b)

Thus, we can find the result of the equation using the same process for summing vectors:

 

Multiplying Vectors By Scalars

Doubling vector -a means doubling its magnitude without changing its direction. The result is represented as 2a.

Generally, k multiplied by a (k.a) represents vector with magnitude k times greater than a but in the same direction.

nb: this is a nostalgic note of mine from a book Manga Guide to Physics

It's Your Mood..! Let's See how We Can Manage it

What you'll receive from life heavily relied on  your effort, and your emotional states aka moods. By the time you are in a positive mood, everything just seem perfect - you can be more productive, doing an effective multi-tasking, and any obstacle you face just feels like nothing. But when you are in a bad mood, you tend to perceive much of everything in negative ways - even a barking dog can turns you into a grumpy cat.  So, most people will agree if I say that mood gives a significant effects on your daily life.

So, if such a thing gives a significant impact to our life, how can we control it? How can we stabilized our emotional states? Many people think that mood is created by external events. When things go as your positive expectation, you are in a good mood, but when things go awfully unexpected  you're going to be in a bad mood, right?

Actually, the statement is neither a valid argument, nor fact. Robert Thayer, a psychologist and the author of Calm Energy, said that mood develops from internal events rather than external events. Robert also said that  

Events are random. Even if you try to plot them down in to a good looking chart, you will find that the correlation between an event and your emotional states is little to none.