# Vector is important to learn physics

lets start first question arises what is vector quantities and why we study vector quantities, what is application for vector quantities, some of question already answered in post “basic concept of vector and scalar” refer that post first then study this post you will understand all concept of vector very well here i will show you one application, vector provide direction and you know what importance of direction also in our life if you have no direction in your life or every moment of your work or activity you can’t reach your destination simply you will wander here and there and time is over, game is over, means wasting of time we have limited time to complete our task accurately for this you have to follow the direction to reach your destination, see picture below.

now unit vector along x axis is i cap ( cap = ^)

unit vector along y axis is j cap

unit vector along z axis is k cap

what is advantage of writing this vector in i,j,k form it makes operation of vector easy addition, subtraction, multiplication and division with similar quantity i,j,k this is main advantage .

with the help of unit vector we can find position of any point in space or 3-D easily following the root of x, y, z axis hence any point suppose p(2,3,5) located in space then we can write this position vector in unit vector form suppose o is origin o(0,0,0)

→ →

op = r = (2-0)i^ +(3-0)j^+(5-0)k^

→

r = 2i^+3j^+5k^

→

where r is full vector and i^, j^, k^ are unit vector similarly any other point can be written as

→ →

r₁ = 2i^+3j^-5k^, r₂ = 2i^-2j^-3k^ now here it is easy to make operation between r,r₁,r₂ vector without using unit vector it was difficult to make operation between r,r₁,r₂ now this can be any vector quantity like displacement, velocity, acceleration, force .

now for magnitude calculation for such type of unit vector

→

suppose r = ai^+bj^+ck^ then its magnitude will be written as

→

|r| = ⎷a²+b²+c² under root square of the a,b,c

**Equal vector condition:**

Two vector are called equal if and only if having equal magnitude and same direction .

→

A →→→→→→

→ here A vector and B vector are equal

B →→→→→→

**Negative vector: **having equal magnitude in opposite direction

→

A→→→→→→

→

←←←←←←B

**Col linear vector**** : **vector having same direction but different magnitude

→

A →→→→→→

→

B →→→

**Co planer Vector :** vector in same plane having different magnitude and direction

→ →

A →→→→→→ B

↙

↙

↙

**Null Vector or Zero Vector: **Vector having Zero magnitude but having direction a point is a null vector or zero vector here its magnitude is zero then what is direction answer is any direction a point has any direction simply add two opposite vector what will be result its magnitude will be zero null since it is a vector addition hence result will be also a vector pointing towards any direction.

addition and subtraction of null vector with other vector not effect vector but multiplication becomes zero.

**Important : ** what is difference between A and |A| here simple A indicate that quantity is scalar only magnitude but |A| indicates it is a vector quantity but we are only interested for magnitude this is the difference . there all vector having great application in whole physics we will study latter where vector concept will be very important so focus ton command over vector and be yourself as vector direction to reach your destination.

thanks for learning **Vector is important to learn physics **

dated 26th May 2018

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