Scalars and Vectors Physics Class 11 Notes | Sticky Notes

 

Scalars and Vectors physics 

Scalars:

The physical quantities having just magnitude and unit but no direction are called scalars.

Example:

Length

Mass

Time

Speed

etc.

Scalars are represented by simple Alphabets.

We can perform addition, subtraction, multiplication and division by simple airthematic rule.

Scalars * Scalars = Scalars

Scalars + Scalars = Scalars

Scalars - Scalars = Scalars

Scalars / Scalars = Scalars

 

Vectors: 

Those physical quantities which have magnitude and unit as well as direction are called vectors.

Example:

Force

Acceleration

Velocity

Torque

Momentum

etc.

Vectors can be represented by arrow on top of alphabets.

Vectors can perform airthematic operations using graphical representation and formulae.

 

Distance is a physical quantity in which only length between two point is considered.

But in Displacement there is direction as well.

How to draw vectors

Vectors can be drawn using suitable scales.

Negative magnitude reverses the direction of vectors.

F = 100N towards east.

Let suppose 20N = 1cm

So, 100N = 5cm

          5cm

 

There are four ways to add vectors:

1.    Hat to tail rule

2.    Using Graph

3.    Parallelogram method

4.    Cosine Law

 Hat to tail rule:

In hat to tail rule first we need to join all vectors in such manner that hat of one vector coincide with tail of second vector.

After joining all vectors draw a line from last vector to first vector and calculate its length. This length is a magnitude of  resultant vector in specific direction.

Here resultant vector is sum of all vectors.

Using graph:

Till now we have studied that vector are in form of its magnitude and direction.

But it can be written in x y and z coordinates