Measurement Chapter 1 Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.

Quantities Physics © 2014 John Wiley & Sons, Inc. All rights reserved. There are two Types of Quantities Physics : 1- Base quantities : (Fundamental Quantities) 2- Derived quantities :

© 2014 John Wiley & Sons, Inc. All rights reserved. Table System International (SI) base quantities SI base quantity Base quantity UnitSymbol length meterm mass kilogramkg time seconds electric current ampereA thermodynamic temperature kelvinK amount of substance molemol luminous intensity or (Unit of intensity of light) candelacd Quantities Physics

© 2014 John Wiley & Sons, Inc. All rights reserved. The three fundamental physical quantities (base quantities) of mechanics are length, mass and time, which in the SI system have the units meter (m), kilogram (kg), and second (s), respectively. These fundamental quantities cannot be defined in terms of more base quantities. Quantities Physics

© 2014 John Wiley & Sons, Inc. All rights reserved. Exercise : (Homework) (SI) The Unit of Length is ……….. The Unit of Time is ……….. The Unit of Electric Current is ……….. The Unit of Temperature is ……….. The Unit of a mount of Substance is ……….. The Unit of Mass is ……….. of more basic quantities. Quantities Physics

© 2014 John Wiley & Sons, Inc. All rights reserved. Derived Quantities: All physical quantities measured by physicists can be expressed in terms of the three basic unit of length, mass, and time. For example, speed is simply length divided by time, and the force is actually mass multiplied by length divided by time squared. Derived quantities: area, speed, volume, density. Quantities Physics

© 2014 John Wiley & Sons, Inc. All rights reserved. Quantities Physics

© 2014 John Wiley & Sons, Inc. All rights reserved. Systems of Units :  SI units (used mostly in physics):  length: meter (m)  mass: kilogram (kg)  time: second (s) This system is also referred to as the MKS system for meter-kilogram- second. Quantities Physics

© 2014 John Wiley & Sons, Inc. All rights reserved.  Gaussian units (used mostly in chemistry):  length: centimeter (cm) cm = 0.01 m  mass: gram (g) g= kg  time: second (s) This system is also referred to as the CGS system for centimeter-gram-second. Quantities Physics

© 2014 John Wiley & Sons, Inc. All rights reserved.  British engineering system (FPS) :  length: foot (ft) ft = 0.30 m  mass: bound bt= 0.45 kg  time: second (s) Quantities Physics

© 2014 John Wiley & Sons, Inc. All rights reserved. 1 km = 1000 m (meters) 1 Km is equivalent to miles. ? Conversion Unit

© 2014 John Wiley & Sons, Inc. All rights reserved. Example (H.W.) : How many m/s are there in 5.0 mi/h 1 inches (in) = 2.54 cm Example (H.W.) : Convert 3 cm to …….in ? Example (H.W.) : Convert 6 in to ………cm ? Example (H.W.) : Convert 120 mile to ……km ? Example (H.W.) : Convert 19 km to ………mile ? Conversion Unit

Scientific notation Scientific notation employs powers of 10 to write large or small numbers Example : (H.W.) (H.W.) A conversion factor is Example : Convert 2 hr to. …… min

© 2014 John Wiley & Sons, Inc. All rights reserved. PrefixSymbolPrefixSymbol X=18exaEdecid 15petaP-2centic 12teraT-3millim 9gigaG-6micro 6megaM-9nanon 3kiloK-12picop 2hectoh-15femtof 1decada-18attoa Power of ten prefixes :