Question

Sir,as said that vector quantities measure both direction as well as magnitude and scalor just me sure the direction so on what basis or from what terms these two names vector and scalor are derived

Answer 1

Scalars are physical quantities which have only a number value or a size (magnitude). A scalar tells you how much of something there is.
DEFINITION
Scalar
A scalar is a physical quantity that has only a magnitude (size).
For example, a person buys a tub of margarine which is labelled with a mass of
500
500
g
g
. The mass of the tub of margarine is a scalar quantity. It only needs one number to describe it, in this case,
500
500
g
g
.
Vectors are different because they are physical quantities which have a size and a direction. A vector tells you how much of something there is and which direction it is in.
DEFINITION
Vector
A vector is a physical quantity that has both a magnitude and a direction.
For example, a car is travelling east along a freeway at
100
100
km⋅h−1
km·h−1
. What we have here is a vector called the velocity. The car is moving at
100
100
km⋅h−1
km·h−1
(this is the magnitude) and we know where it is going – east (this is the direction). These two quantities, the speed and direction of the car, (a magnitude and a direction) together form a vector we call velocity.
Examples of scalar quantities:
mass has only a value, no direction
electric charge has only a value, no direction
Examples of vector quantities:
force has a value and a direction. You push or pull something with some strength (magnitude) in a particular direction
weight has a value and a direction. Your weight is proportional to your mass (magnitude) and is always in the direction towards the centre of the earth.