Monday, July 13, 2009

Physical quantities and units

Physical quantities

What is a physical quantities?

Subject of formula

Subject of formula: The basics

Vectors

What is a vector and how to add vector

Scalar and vector quantities

How to subtract one vector from another

Units

Base Units

Derived units

Homogeneity of equations 

Prefixes

Prefixes  and how to use them

Measurement of physical quantities

Volume and volume of irregular objects

Prefixes

How to use prefixes

2 comments:

  1. why we need to use correct physical quantities and unit

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  2. First there are different units for the same quantity.
    For example the quantity length can have SI units such as m which is used in France and Imperial units such as the foot that is used in England and the USA.
    One m is approximately 3.1 feet.

    Suppose that some object must be 1 foot that is 30 cm but the person does not write the unit. someone in france who is only used to metre would wrongfully assumed that unit is m and would make the object 1 m long instead of 1 foot. This could be a problem is some case and human life can even be at risk. So to avoid this all quantities must be written in the proper unit to avoid problems.

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