In this post we will discuss about the very first topic of physics unit and measurement. means the starting phase of physics. If you to the even big universities, your physics professor start your first class with this topic i.e, unit and measurement. So, you can imagine how important this chapter is.
Unit and Measurement Introduction:-
Physics:- The study of nature and
natural things.
- It is the made of greek word ” Fusis” means natural
things and nature. - It means that physics is the study of nature and its laws.
- Physics is the foundation of engineering and technology.
- Physics is based in experiment when experiments are done then it
measure with the help of physical quantity. - Quantity means it represents the number.
Physical
quantity:- It is
represent of the physical laws in the term id quantity.
- It is of two types
- Scalar quantity and vector quantity.
- Scalar quantity means it has only magnitude not direction.
- vector quantity means it has both magnitude and as well as
direction.
What is Unit?
It is of two types
- Fundamental unit
- Derived unit
1. Fundamental unit:- It is not depend another unit, three fundamental
unit are mass, length and Time.
2. Derived unit:- It is depend in fundamental unit.
system
of unit are four types
1. Mks system:- In
this system Length, Mass and Time are expressed in meter, Kilogram, and Second.
2. Fps system:- In
this system Length, Mass and Time is expressed in Foot, Pound, second.
3. CGs system:- In
this system Length, Mass and Time is expressed in Centimeter, Gram, second.
4. S.I system;- (
international System of Unit ) In S.I system having seven fundamental unit.
Some examples of physical quantities with their si
units and cgs units
Here is a collection of 5 fundamental and derived physical quantities which commonly used in physics
with their si units and CGS units. Also describe the derived quantity with
derivation.
We have already discussed
about the definition of physical quantity in the above definition. But lets
define the physical quantity in another words.
Physical quantity are
those quantities which represents the quantities of any material with the help
of some symbols attached with numerical values. For example a container
contains 6 kilograms of wheat. So we can write 6 kg. Here kg is the physical
quantity attached with numerical value of 6.
As we have already seen
above that, Physical quantities are two types first is fundamental quantity
and second is derived quantity. These are the following 5 physical
quantities (both fundamental and derived) with their si units and CGS units.
Before we start discussing following 5 physical quantities. Please note that
some quantities are derived from fundamental quantity.
- Mass
- length
- Time
- Acceleration
- Velocity