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Chapter 1

Measurement andUnits

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1.01 Numbers and units 1.02 A system of units

1.03 Measuring length and time

1.04 Volume and density

1.05 Measuring volume and density

1.06 More about mass and velocity

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1.01 Numbers and units

1.02 A system of units

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Introduction to Physics

Physics is the study of natural phenomenaand properties of matter.

Force and

motion

Nuclear

Physics

Electricity and

electromagnetism

Light

Field of study

in physics

WavesHeat

Electronics

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1.01 Numbers and units

Physical quantities are

quantities that can be

measured.

The value of the

measurement consistsof a numerical

magnitude and a units.

Physical

Quantity

Base

Quantity

Derived

Quantity

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Base Quantities

Base quantities are physical

quantities that cannot be defined interm of others quantities.

SI International System of Units

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The seven base quantities

are Length

Mass Temperature

Time

Electric currentAmount of substance

Luminous intensity

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Quantity Unit Symbol

Length Meter m

Mass Kilogram kg

Time Second s

Temperature Kelvin K

Current Ampere A

Amount ofsubstance

Mole mol

Luminous

intensity

candela cd

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The five important base quantities:

Base Quantity Symbol SI Unit Symbol of SI

unit

Length l Metre m

Mass m Kilogram kg

Time t Second s

Temperature T Kelvin K

Current I Ampere A

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Derived quantities are physical quantities derived

from combination of base quantities through

multiplication or division or both multiplication and

division.

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Prefixes are used to simplify the description of physical quantities that

are either very big or very small.

Prefix Symbol Value

Tera T 1012

Giga G 109

Mega M 106

Kilo k 103

Hecto ha 102

Deca da 101

Deci d 10-1

Centi c 10-2

Milli m 10-3

Micro 10-6

Nano n 10-9

Pico p 10-12

Thanks God My Killer Husband Died During Christmas Makes Me Not Petrified

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Standard form or scientific notation is used

to express magnitude in a simpler way.

In scientific notation, a numerical

magnitude can be written as:

Examples

The distance between the Earth and the Sun= 150 000 000 000 m

= 1.5 x 1011 m

A x10n

, where 1 A < 10 and n is an integer.

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Example 1

1. 0.00000008 m ? m

= 8 x 10-8 m

2. 75 000 000 kg

? kg= 7.5 x 107 kg

3. 0.0007766 m ? m= 7.766 x 10-4 m

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Example 2

1. 8 cm ? m

= 8 x 10-2 m

2. 75 00 kg

g= 7.5 x 103 x 103 g

= 7.5 x 106 g

3. 0.776 mm ? m

= 7.76 x 10-1 x 10-3 m

= 7.76 x 10-4 m

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Exercise 1

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Exercise 2

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Exercise 3

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1. 0.03 m ? cm

2. 50 milliseconds ? Seconds

3. 94.6 MHz ? Hz

Exercise 4

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4. 1 000 000 mm ? km

5. 0.0005 Mg ? g