# Content

• Physics

Physics is a branch of science that involves the study of physical world : energy, matter and how they are related. For example, study of motion of electron, rocket, energy released during the explosion of atomic bomb, energy  in waves, electronic circuits, structure of protons and of universe etc.

Mathematics and Physics

Physics uses mathematics as a powerful tool.  Many physics laws are expressed in terms of mathematical forms and formulas.

Units

1. SI Unit being used in Physics

(International System of Units-SI units)

Quantity                     Base Unit            Symbol

Mass :                           Kilogram           kg

Temperature                   kelvin               k

Length :                         meter               m

Amount of substance       mole                 mol

Time:                             second              s  or sec

Electric current               ampere             A

Luminous intensity          candela             cd

Three Fundamental Units being used in mechanics

 Mass Length Time kg m  (meter) s (second)

 Prefix 1000m 10n Decimal English word Adoption[nb 1] Name Symbol Short scale Long scale yotta Y 10008 1000000000000000000000000 septillion quadrillion 1991 zetta Z 10007 1000000000000000000000 sextillion thousand trillion or trilliard 1991 exa E 10006 1000000000000000000 quintillion trillion 1975 peta P 10005 1000000000000000 quadrillion thousand billion or billiard 1975 tera T 10004 1000000000000 trillion billion 1960 giga G 10003 1000000000 billion thousand million or milliard 1960 mega M 10002 1000000 million 1960 (1873) kilo k 10001 1000 thousand 1960 (1795) hecto h 10002/3 100 hundred 1960 (1795) deca da 10001/3 10 ten 1960 (1795) 10000 1 one – deci d 1000−1/3 0.1 tenth 1960 (1795) centi c 1000−2/3 0.01 hundredth 1960 (1795) milli m 1000−1 0.001 thousandth 1960 (1795) micro μ 1000−2 0.000001 millionth 1960 (1873) nano n 1000−3 0.000000001 billionth thousand millionth 1960 pico p 1000−4 0.000000000001 trillionth billionth 1960 femto f 1000−5 0.000000000000001 quadrillionth thousand billionth 1964 atto a 1000−6 0.000000000000000001 quintillionth trillionth 1964 zepto z 1000−7 0.000000000000000000001 sextillionth thousand trillionth 1991 yocto y 1000−8 0.000000000000000000000001 septillionth quadrillionth 1991

3. Standard Abbreviations for Unit Names:

s  = second   N = newton   V = volt     cm = centimeter  lb = pound   m  = meter  J  = joule

W = watt     ft = foot       Hz = hertz   A = Ampere      g  = gram    mi = mile    C = coulomb

kg = kilogram

4.Examples

Unit conversion

5 nm= 5 nanometer = 5x 10 - 9 meter

3 giga seconds = 3x 109 s

Complete the following chart:

mm                  cm                    m                    km

1.0    =                   =                      =           _____

=           25     =                     =

=                    =            3.71   =

5. Homework