pdt 180 engineering science munira mohamed nazari school of bioprocess, unimap

PDT 180PDT 180ENGINEERING SCIENCEENGINEERING SCIENCE

MUNIRA MOHAMED NAZARI

SCHOOL OF BIOPROCESS, UNIMAP

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

pdt 180 engineering science munira mohamed nazari school of bioprocess, unimap

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