PDT 180 ENGINEERING SCIENCE MUNIRA MOHAMED NAZARI SCHOOL OF BIOPROCESS, UNIMAP

Powerpoint Templates Page 2 Powerpoint TemplatesUNITS OF MEASUREMENT

Powerpoint Templates Page 3 TOPIC OUTLINE INTRODUCTION UNIT, STANDARDS & THE SI SYSTEM MEASUREMENT & UNCERTAINTY; SIGNIFICANT FIGURES CONVERTING UNITS

Powerpoint Templates Page 4 Course outcome (co) Ability to analyze problems related to units of measurements, and scalar and vector quantities. CO 1

Powerpoint Templates Page 5 INTRODUCTION Why we learn “Unit and Measurements”? –First important aspect in any technical course study. –As we always need to measure any quantity. For example, the length of the table. –If we get the numerical value for the length of the table as 2, then we must compare that length relatively with a particular standard or unit.

Powerpoint Templates Page 6 UNIT, STANDARDS & THE SI SYSTEM

Powerpoint Templates Page 7 UNIT, STANDARDS & THE SI SYSTEM UNIT –The measurement of any quantity is made relative to a particular standard or unit and this unit must be specified along with the numerical value of the quantity. –Unit used should always be stated. STANDARD UNIT QuantityStandard Unit LengthMeter (m) TimeSecond (s) MassKilogram (kg)

Powerpoint Templates Page 8 SYSTEMS OF UNITS –Two types systems of units, English unit (inches, feet, or miles) Metric unit (centimeters, meters, or kilometers) –When dealing with the laws and equations of physics it is very important to use a consistent set of units. –Today the most important is the Systeme International (SI). –In SI units, the standard of length is meter, time is second and mass is kilogram. HOWEVER…

Powerpoint Templates Page 9 BASE vs DERIVED UNITS –Physical quantities can be divided into two categories; Base quantities Base unit (single) Derived quantities Derived unit (multiple) –SI Base Quantities and Units Corresponding units QuantityUnitUnit Abbreviation Lengthmeterm Timeseconds Masskilogramkg Electric currentampereA TemperaturekelvinK Amount of substancemolecd

Powerpoint Templates Page 10 MEASUREMENT & UNCERTAINTY; SIGNIFICANT FIGURES

Powerpoint Templates Page 11 In the metric system, the larger and smaller units are defined in multiples of 10 from the standard or base unit. This is to makes calculation easier. For example; –1 km = 1000 m, while 1 cm = 1/100 The prefixes “kilo-”, “centi-” and others can be applied to all units either base unit or derived unit. For examples; –A kilowtt (kW) is 1000 watt (W) and, –1 milisecond (msec) is 1/1000 sec or

Powerpoint Templates Page 12 Table below lists some of the Metric (SI) prefixed used in engineering and technical computation. PrefixeMeaningAs numbersSymbols KiloThousand1000k MegaMillion M GigaBillion G CentiHundredth0.01c MiliThousandth0.001m MicroMilionth µ NanoBillionth n

Powerpoint Templates Page 13 CONVERTING UNITS

Powerpoint Templates Page Conversion Factor A ratio of equivalent values of a quantity expressed in different units. To convert a quantity expressed in terms of one unit to its equivalent in terms of another unit by multiply the given quantity by the conversion factor (new unit/old unit).

Powerpoint Templates Page 15 Example: –To convert 36 mg to its equivalent unit in grams (g). – or mg 1 g 1000 mg = g Vertical line Multiplication symbol

Powerpoint Templates Page 16 Example: –Convert an acceleration of 1 cm/s 2 to its equivalent in km/h 2. –Express the following sum using SI unit and with correct number of significant figures: 1.0 m cm x = 16 Answer = km/h 2 Answer = m

Powerpoint Templates Page 17 Thank you