1.2 base derived quantities

1.2 Base & Derived Quantities1.2 Base & Derived Quantities

www.myfunphysicsworld.blogspot.comwww.myfunphysicsworld.blogspot.com

Chapter 1 Chapter 1 Introduction To PhysicsIntroduction To Physics

Learning OutcomesLearning Outcomes


PHYSICAL QUANTITYPHYSICAL QUANTITY

Wow! Is this real??!

Hehehe…. Can u guess what is my

height?

Weight Mass Timewww.myfunphysicsworld.blogspot.comwww.myfunphysicsworld.blogspot.com

PHYSICAL QUANTITYPHYSICAL QUANTITY

The quantity that The quantity that can be measuredcan be measuredMeasurable :Measurable :The process of determining the The process of determining the value of a quantity using a scientific value of a quantity using a scientific instrument with a standard scaleinstrument with a standard scaleExample:Example:Mass, weight, height, time, Mass, weight, height, time, temperaturetemperature


Length of meter ruler = 100.0 cmLength of meter ruler = 100.0 cm

Which isWhich is

1. Physical quantity?1. Physical quantity?

2. Numerical value?2. Numerical value?

3. Unit of measurement?3. Unit of measurement?


Non-physical QuantityNon-physical Quantity

The quantity that The quantity that cannot be cannot be measuredmeasured..

Example:Example:

Feelings-happy Feelings-happy , sad , sad , , angry ….angry ….


Physical Quantities

Base Quantities Derived Quantities


Base QuantityBase Quantity Derived QuantityDerived Quantity

Physical quantities Physical quantities that that cannot be cannot be defineddefined in terms of in terms of other other physical physical quantitiesquantities

Physical quantities Physical quantities derived from base derived from base quantitiesquantities by by multiplication or multiplication or division or bothdivision or both

Length, Mass, Length, Mass, Time, Time, Temperature, Temperature, Electric CurrentElectric Current

Density, Pressure, Density, Pressure, Force….Force….


Base QuantitiesBase QuantitiesPhysical quantities that cannot be defined Physical quantities that cannot be defined in terms of other physical quantities.in terms of other physical quantities.Unit : base unitUnit : base unit

Name & SymbolName & Symbol S.I. Unit & SymbolS.I. Unit & Symbol

Length / lLength / l meter / m meter / m

Mass / mMass / m kilogram / kgkilogram / kg

Time / tTime / t second / ssecond / s

Temperature / TTemperature / T kelvin / Kkelvin / K

Electric Current / Electric Current / II ampere / Aampere / Awww.myfunphysicsworld.blogspot.comwww.myfunphysicsworld.blogspot.com

Derived QuantitiesDerived QuantitiesPhysical quantities derived from base quantity Physical quantities derived from base quantity (multiplication or division or both)(multiplication or division or both)

Unit : Derived UnitUnit : Derived Unit

Name & SymbolName & Symbol S.I. Unit & SymbolS.I. Unit & Symbol

Velocity / vVelocity / v meter per second / msmeter per second / ms-1-1

Force / FForce / F Newton / NNewton / N

Pressure / PPressure / P Pascal / PaPascal / Pa

Weight / WWeight / W Newton / NNewton / N

Density / Density / ρρ kg mkg m-3 -3 www.myfunphysicsworld.blogspot.comwww.myfunphysicsworld.blogspot.com

DERIVED QUANTITIESDERIVED QUANTITIES


(a) Show the relationship between the (a) Show the relationship between the following derived quantities and their following derived quantities and their corresponding base quantities.corresponding base quantities.

(b) Derive the units for the following (b) Derive the units for the following physical quantitiesphysical quantities

Density Density = mass / volume= mass / volume

= mass / (length)= mass / (length)33

= kg m= kg m-3-3


PrefixPrefix SymbolSymbol ValueValue

TeraTera TT 10101212

GigaGiga GG 101099

MegaMega MM 101066

KiloKilo k k 101033

HectoHecto h h 101022

DecaDeca dada 101011

DeciDeci d d 1010-1-1

CentiCenti cmcm 1010-2-2

MilliMilli mm 1010-3-3

MicroMicro ųų 1010-6-6

NanoNano nn 1010-9-9

picopico pp 1010-12-12

4amanah 10jan until here4amanah 10jan until here

Ask them to memorise prefixes follow text Ask them to memorise prefixes follow text bookbook

Ask to collect rm1 by next weekAsk to collect rm1 by next week

30 students30 students


Changing UnitChanging Unit


PrefixPrefix ValueValue

Tera / TTera / T 10101212

Giga / GGiga / G 101099

Mega / MMega / M 101066

Kilo / kKilo / k 101033

Hecto / hHecto / h 101022

Deca /daDeca /da 101011

Deci / dDeci / d 1010-1-1

Centi/cmCenti/cm 1010-2-2

Milli / mMilli / m 1010-3-3

Micro / Micro / ųų 1010-6-6

Nano / nNano / n 1010-9-9

Pico / pPico / p 1010-12-12

10-6-(3) =10-9

1.23 ųmųm

= 1.23 x 10-6-(3) km

= 1.23 x 10-9 km

10(A) -(B)

A = initial prefix

B = final prefix

1.23 ųm ųm = _____ km


PrefixPrefix ValueValue

Tera / TTera / T 10101212

Giga / GGiga / G 101099

Mega / MMega / M 101066

Kilo / kKilo / k 101033

Hecto / hHecto / h 101022

Deca /daDeca /da 101011

Deci / dDeci / d 1010-1-1

Centi/cmCenti/cm 1010-2-2

Milli / mMilli / m 1010-3-3

Micro / Micro / ųų 1010-6-6

Nano / nNano / n 1010-9-9

Pico / pPico / p 1010-12-12

106-(-9)= 1015

4.56 Mg

= 4.56 x 106-(-9)

= 4.56 x 1015 ng

4.56 Mg = _____ ng


Change to S.I. UnitChange to S.I. Unit

456 g/cm456 g/cm33

= = 456 g456 g

cmcm33

= = 456 x 10456 x 10-3 -3 kgkg

1 x (101 x (10-2-2 m) m)33

= = 456 x 10456 x 10-3 -3 kgkg

1 x 101 x 10-6-6 m m33

=456 x 10=456 x 10-3 -3 x 10x 1066 kg m kg m-3 -3

= 456 x 10= 456 x 1033 kg m kg m-3 -3

= 4.56 x 10= 4.56 x 1055 kg m kg m-3-3


Exercise 1Exercise 1

January 2011January 2011


For the following physical quantities, For the following physical quantities, derive theirderive theiri) base quantitiesi) base quantitiesii) units ii) units

(a)(a) VelocityVelocity

(b)(b) AccelerationAcceleration

(c)(c) ForceForce

(d)(d) WorkWork

(e)(e) DensityDensity

1


Derived Quantities

Base Quantities Units

a)Velocity displacement/time= length/time

m/s

b) Acceleration

c) Force

d) Work

e) Densitywww.myfunphysicsworld.blogspot.comwww.myfunphysicsworld.blogspot.com

(a) Velocity(a) Velocity

= displacement/time= displacement/time

= length/time= length/time

= m/s= m/s

= m s= m s-1-1


(b) Acceleration(b) Acceleration

= = Change in VelocityChange in Velocity

timetime

= = lengthlength

(time)(time)22

==m/sm/s22

==m sm s-2-2


(c) Force(c) Force= mass x acceleration= mass x acceleration

= mass x = mass x lengthlength

(time)(time)22

= kg m s= kg m s-2-2

= Newton= Newton

= N = N


(d) Work(d) Work

= Force x Displacement= Force x Displacement

= mass x acceleration x length= mass x acceleration x length

= mass x = mass x lengthlength x length x length

(time)(time)22

== kg m kg m22 s s-2-2

= Nm = J= Nm = J


e) Densitye) Density

= = massmass

volumevolume

= = massmass

(length)(length)33

= kg m= kg m-3-3


Derived Quantities

Base Quantities Units

a)Velocity displacement/time= length/time

m/s

b) Acceleration Change in Velocity/time= length/(time)2

m/s-2

c) Force Mass x acceleration= (mass)(length) (time)2

d) Work Force x displacement=


Show the relationship between Show the relationship between the following derived the following derived quantities and their quantities and their corresponding base corresponding base quantities.quantities.

(a) acceleration(a) acceleration(b) momentum(b) momentum

2


3


1.2 base derived quantities

Documents

base derived quantities

mass x acceleration

physical quantities

following derived quantities

corresponding base quantities

mass x length x length

mass x length time2

base unit