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

PDT 180PDT 180ENGINEERING SCIENCEENGINEERING SCIENCE

MUNIRA MOHAMED NAZARI

SCHOOL OF BIOPROCESS, UNIMAP

Powerpoint TemplatesPage 2

Powerpoint Templates

UNITS UNITS OF OF

MEASUREMENTMEASUREMENT


TOPIC OUTLINETOPIC OUTLINE

• INTRODUCTION

• UNIT, STANDARDS & THE SI SYSTEM

• MEASUREMENT & UNCERTAINTY; SIGNIFICANT FIGURES

• CONVERTING UNITS


Course outcome (co)Course outcome (co)

Ability to analyze problems related to units of measurements, and scalar and vector quantities.

CO 1


INTRODUCTIONINTRODUCTION• 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.


UNIT, STANDARDS & THE SI UNIT, STANDARDS & THE SI SYSTEM SYSTEM


UNIT, STANDARDS & THE SI UNIT, STANDARDS & THE SI SYSTEMSYSTEM• 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 UNITQuantity Standard Unit

Length Meter (m)

Time Second (s)

Mass Kilogram (kg)


• 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…


• 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

Corresponding units

Quantity Unit Unit Abbreviation

Length meter m

Time second s

Mass kilogram kg

Electric current ampere A

Temperature kelvin K

Amount of substance mole cd


MEASUREMENT & MEASUREMENT & UNCERTAINTY; UNCERTAINTY;

SIGNIFICANT FIGURESSIGNIFICANT FIGURES


• 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 m @

• 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

m 10 2

sec 10 3


• Table below lists some of the Metric (SI) prefixed used in engineering and technical computation.

Prefixe Meaning As numbers Symbols

Kilo Thousand 1000 k

Mega Million 1 000 000 M

Giga Billion 1 000 000 000 G

Centi Hundredth 0.01 c

Mili Thousandth 0.001 m

Micro Milionth 0.000 001 µ

Nano Billionth 0. 000 000 001 n

10 2

103

10 3

10 6

10 9

109

106


CONVERTING UNITSCONVERTING UNITS


14

Conversion Factor

A ratio of equivalent values of a quantity expressed in different units.

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).


• Example:– To convert 36 mg to its equivalent unit in grams

(g).

– or

15

g 0.036 )mg 1000

g 1( ) 36( mg

36 mg 1 g 1000 mg

= 0.036 g Vertical line

Multiplication symbol


• Example:– Convert an acceleration of 1 cm/s2 to its

equivalent in km/h2.

– Express the following sum using SI unit and with correct number of significant figures:

1.0 m + 14.25 cm + 1.24 x =

16

Answer = 129.6 km/h 2 Answer = 129.6 km/h 2

m 105

Answer = 1.2665 mAnswer = 1.2665 m


Thank youThank you

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