Vector quantity: -
What is a physical quantity?
Any quantity that can be measured is a physical quantity.
Physical quantities are classified as vectors and scalars
The physical quantities, which require only magnitude for their complete specification, are called scalars or scalar quantity.
They can be added up based on ordinary rules of algebra.
Quantities such as mass, temperature, speed, time, density, etc., are scalars.
Consider a freely falling body under the action of gravity.
Here the motion of the body is one-dimensional and hence the distance traveled in a given time is a scalar.
The motion of the coins on a carom board is two-dimensional.
Similarly when a spacecraft moves in space the motion will be three-dimensional. Here the concept of direction becomes more primal.
Now there is a need to define a quantity, which has both magnitude and direction.
Such quantities are referred to as vectors or vector quantities.
Velocity, acceleration, weight, force, momentum, etc., are vectors.
Representation of vectors: -
A vector is represented by a straight line with an arrowhead.
The length of the line is equal to or proportional to the magnitude of the vector and the arrowhead shows the direction.
Types of vectors: -
Vectors can be classified as-
collinear vectors
co-initial vectors
negative vectors
zero or null vectors
position vectors
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