physics: chepter # 1

physics:-

physics deal with the study of matter and energy and the relationship between them

Base Quantities:-

Base quantities are the minimum number of those physical quantities in term of which other quantities

can be defined.

example:-

Length, mass, time,etc

Derived Quantities

derived quantities are those physical quantities whose definition are based on other physical quantities
example:- velocity, acceleration, force, etc.

The general conference on weights and measures has not yet classsified certain units of the SI under either base units or deriveds units.These SI units are called supplementary units.there are two types of supplementary units.

Radian:-

Radian is the plane angle between two radius of a circle which cut off on the circumferncs an arc, equal in lenght to radius.

Steradian:-

The Steradian is solid angle subtended at the center of sphere by an area of it surface equal to the squares of radius of sphere.

errors in measurement

there are two types of measurement
1:-random error
2:-systematic error

Random error:-

This error is due to unknown cause and fluctuations in the quantity being measured.

systematic error:-

error due to incorrect design or calibrations of a measuring device are called systematic error.

Define significant figures:-

In any measurement the accurately known digits and first doubtful digits are called significant figures.

precision:-

A precision measurement is the one which has less absolute uncertainty.

Accuracy:-

The accuracy of mearurement is the extant to which systematic errors make a measured value. the accuracy of measurement can be indicated by the number of significant figures or by stated uncertainty.