Physical Quantities Physical Quantity Name of Unit Abbreviation

Physical Quantities: Physical Quantity Name of Unit Abbreviation ﺃﺴﻢ ﺍﻟﻮﺣﺪﺓ ﺃﺨﺘﺼﺎﺭ ﺍﻟﻮﺣﺪﺓ Kilogram Kg meter m Time Second s Temperature Kelvin K Electric Current Ampere A mole mol. candela cd ﺍﻟﻜﻤﻴﺎﺕ ﺍﻟﻔﻴﺰﻳﺎﺋﻴﺔ Mass Length Amount of Substance Luminous Intensity

Derivative Units (1) Density: The density of a material is defined as its mass per unit volume. D = mass / volume D = Kg / m 3 (2) Volume: length x high x width V = m 3 (3) Speed: the distance traveled per unit of time. Speed = distance / time S = m / s = ms-1 (4) Acceleration: is the change in velocity over time. Acceleration = Speed / Time A = ms-1 / s = ms-2 (5) Force: is that which can cause an object with mass to change its velocity. Force = acceleration x mass F = ms-2 x Kg = Kgms-2 (6) Pressure: is the force per unit area applied to an object in a direction perpendicular to the surface. Pressure = Force / Area P = Kgm-1 s-2 (Pascal, Pa) (7) Energy: that describes the amount of work that can be performed by a force. Energy = Force x Distance E = Kgms-2 x m = Kgm 2 s-2 (Joule, J)

Temperature The temperature is measured with thermometer, No Kidding!!! Three systems of measuring temperature are widely used: 1 - The Celsius Scale 2 - The Kelvin Scale 3 - The Fahrenheit Scale o C K o. F The first two temperature systems are used in the physical science and the third is used in many of the engendering sciences. The fundamental difference between the first two systems is in their zero points. Temperature (Kelvin) = temperature (Celsius) + 273 Temperature (Celsius) = Temperature (Kelvin) -273 Exc. Normal body temperature is 37 o. C. Convert this temperature to the Kelvin scale. Answer: T (K) = 37 o. C + 273 = 310 K

The prefixes used in the SI System Prefix ﺍﻷﻤﺎﻣﻲ ﻟﻠﻮﺣﺪﺓ Symbol ﺍﻟﻤﻘﻄﻊ ﺍﻟﺮﻣﺰ Exponential Notation Tera T 1 x 1012 m Giga G 1 x 109 m Mega M 1 x 106 m Kilo K 1 x 103 m Deci d 1 x 10 -1 m Centi c 1 x 10 -2 m Milli m 1 x 10 -3 m Micro µ 1 x 10 -6 m Nano n 1 x 10 -9 m Pico p 1 x 10 -12 m angestrom Ao 1 x 10 -10 m 1 km = 1 mg = m kg mm g pm µg pg