PHYSICS

FORM 4

Chapter 1

Introduction to Physics

Edited by In collaboration with

Cikgu Desikan Cikgu Khairul Anuar

SMK Changkat Beruas, Perak SMK Seri Mahkota, Kuantan

Chapter 1

Introduction to Physics

Dear students,

With the new day comes new strength and new

thoughts.

Learning Objectives :

FORM 4 PHYSICS

1. Understanding Physics

2. Understanding base quantities and derived quantities

3. Understanding scalar and vector Quantities

4. Understanding measurements

5. Analysing scientific investigations

2016 2007 2008 2009 2010 2011 2012 2013 2014 2015

Analysis of Past Year Questions

P1 3 3 3 2 3 3 4 1

A - - - 1 - 1 - -

P2 B - - - - - - - -

C - - - - - - - -

A - 1 1 1 - - 1 -

P3

B - - - - - - - -

Chapter 1

Introduction to Physics

Dear students,

By failing to prepare, you are preparing to fail !!!

Concept Map

Introduction to Physics

Physics Physics Quantity Measurement Scientific

Concepts Investigation

Base Derived Approximation

Field of Quantity Quantity

Physics

Instrument for

Base Unit Derived Unit Measurement

Error

Prefix Scientific

Notation

Accuracy

Conversion of

Units Sensitivity Consistency

1.1 Understanding Physics

What is Physics?

Physics is the study to find a rational explanation (why and how) about the nature of matter,

energy and natural phenomena.

Heat

2. _________________

Studies the influence of

heat on different

Light

types of matter 3. ________________

Forces Motion

1.__________ & ________ Explains the different

Investigate the action of phenomena due to light

force and motion

Waves

Fields of study 4. _________________

in physics Understand the

Nuclear Physics

7. ______________ properties of different

types of waves and

Study of nuclear their uses

structure and their

application

Electronics

Electromagnetism

6. ___________ 5. _______________

Studies the use of Investigates the

electronic devices in interactions of electric &

various fields magnetic fields

4

1.2 Physical Quantities

Physical Quantities is a physical 1 Base quantities

characteristic that can be measured.

Base quantities are quantities that cannot be

derived

All physical quantities can be classified ___________ in terms of other base quantities.

into two groups :

Symbol

Base quantities

1. ____________________________

Base quantity Symbol S.I. Unit for S.I.

Derived quantities

2. ____________________________ Unit

Length L meter m

Derived quantities 2

Mass m kilogram kg

Derived quantity is one which obtained by

__________________ base quantities by Time t second s

combining

multiplication, division or both these Current I Ampere A

operations. Its unit is derived from a

similar combination of the base units. Temperature T Kelvin K

Derived quantities

(symbol) Expressed in base quantities Derived units

Area, A Area = length x width m 2

Volume, V Volume = length x width x height m 3

5

Derived

quantities Expressed in base quantities Derived units

(symbol)

Mass

Density , ρ Density kgm –3

Volume

nt

Displaceme

Velocity , v Velocity ms –1

Time

Change in velocity

Acceleration, a Accelerati on ms –2

Time

Momentum, p Momentum = mass x velocity kgms –1

Force, F Force = mass x acceleration N / kgms –2

Force

–1 –2

Pressure, P Pressure Nm / Pa / kgm s

–2

Area

Weight, W Weight = mass x gravitational acceleration N / kgms –2

6

Scientific form Prefixes

The values of measurements which is either Prefix is used to simplify the expression of very

very large of very small are written in big or very small numerical values of physical

Standard Form so as to be neater, brief and quantities

easier to read.

n

A x 10 , Prefix Value Standard Symbol

1 < A < 10 and n = integer form

1,000,000,000,

Tera 10 12 T

Write the following quantities in standard 000

form : Giga 1,000,000,000 10 9 G

a. Radius of the earth = 6 370 000 m Mega 1,000,000 10 6 M

Ans : 6.37x 10 m Kilo 1,000 10 3 k

6

Hecto 100 10 2 h

b. Mass of an electron 1

= 0.000 000 000 000 000 911 kg Deca 10 10 da

Deci 0.1 10 −1 d

Ans : 9.11x 10 -16 kg

Centi 0.01 10 −2 c

c. Size of a particle = 0.000 03 m Mili 0.001 10 −3 m

Ans : 3 x 10 m Micro 0.000 001 10 −6 μ

-5

d. Diameter of an atom = 0.000 000 072 m Nano 0.000 000 001 10 −9 n

Ans : 7.2 x 10 m 0.000 000 000

-8

Pico 001 10 −12 p

e. Wavelength of light = 0.000 000 55 m

-7

Ans : 5.5 x 10 m 7

Exercise 3.1

Conversion of Units

Convert each of the following measurements

into metre, m

(a) 2.98 Tm (a) 2.98 x 10 12 m

3

(b) 298 km (b) 2.98 x 10 m

-6

(c) 2.98 μm (c) 2.98 x 10 m

8

-1

(d) 2.98 x 10 Gm (d) 2.98 x 10 m

3

-3

(e) 2.98 x 10 Mm (e) 2.98 x 10 m

7

(f) 29.8 x 10 nm (f) 2.98 x 10 -2 m

(g) 298 x 10 μm (g) 2.98 x 10 -2 m

4

8

Convert

2

a. 4 m into the units of cm 2

2

b. 30 cm into the units of m 2

2

c. 2.5 m to unit of mm 2

2

d. 500 mm into the units of m 2

e. 200 m into the units of mm 3

3

3

f. 11.5 cm into the units of m 3

-1

g. 72 km h into the units of ms -1

-3

h. 5 g cm into the units of kg m -3

4

a) 4 x 10 m 2

-3

b) 3 x 10 m 2

6

c) 2.5 x 10 m 2

-4

d) 5 x 10 m 2

e) 2 x 10 m 2

11

-5

f) 1.15 x 10 m 2

g) 20 ms -1

h) 5000 kgm -3

9

1.3 Scalar and Vector Quantities

Scalar Quantities Vector Quantities

Quantities that have magnitude but no Quantities that have both magnitude

direction and direction

Distance Displacement

Speed Velocity

work Acceleration Examples

Area Force

Mass Momentum

Distance(s) Displacement(s)

Distance between two points measured along a

Total length of the path traveled

specific direction

Scalar quantity Vector quantity

Speed Velocity

Rate of change of distance Rate of change of displacement

nt

distance displaceme

Speed = Velocity =

time time

Scalar quantity Vector quantity

10

1.4 Measuring Instruments

Consistency Accuracy Sensitivity

Consistency in Accuracy of a measurement Sensitivity of an instrument is

measurements refers to how is how close the its ability to detect a small

little deviation there is measurement made is to the change in the quantity to be

among the measurements actual value of the quantity. measured in a short period

made when a quantity is of time.

measured several times.

The diagram shows the result for four shooters A, B, C and D

in a tournament. Every shooter shot five times.

Shooter Consistency Accuracy

A High Low

B Low High

C High High

D Low Low

(Use High / Low)

11

ERROR

Error is uncertainty caused by measuring instrument or the observer or the physical factors

of the surroundings.

Systematic Error Random Error

Caused by:

Caused by: i. Surroundings factors, such as

i. Condition of the measuring instrument temperature and wind

ii. Condition of environment

ii. Carelessness of the observer

Example Example

zero error

i. ______________________________ i. Parallax error ii. Error in counting

ii. Inaccurate calibration iii. Natural errors (sudden change)

Way of correction Ways of correction

i. Proper calibration i. Take several readings and calculate

ii. Adjust the instrument frequently the average value.

Parallax Error

A parallax error is an error in reading an instrument because the observer’s eyes and pointer are

not in line / perpendicular to the plane of the scale.

How to avoid parallax error?

o

1. position of eyes must be in line/ perpendicular / 90 with the scale of the reading to be taken.

2. When taking reading from an ammeter, we must make sure that the eyes are exactly in front of

the pointer, so that the reflection of the pointer in the mirror is right behind the pointer. In other

words, the reflection of the pointer on the mirror could not be seen by the observer, then it is

free from parallax error. 12

Parallax Error

16 A 13

B Reading = 15.1 ml

A

Reading = 2.6 cm 15 B

C

Reading = 2.5 cm Reading = 15.0 ml

Reading = 2.7 cm

1 2 3 14 C

Reading = 14.9 ml

Accurate reading = 2.6 cm

Pointer’s image can be seen Pointer’s image is behind the pointer

Measuring Instruments & Accuracy

Physical Quantity Measuring Instrument

Length Pembaris meter, Angkup vernier , Tolok skru mikrometer

Current Ammeter

Mass Neraca tiga palang

Temperature Termometer

Time Jam randik (analog, mekanikal)

Voltage Voltmeter

Outside jaws

Measure external diameter VERNIER CALLIPER

of an object

Vernier

scale Main scale

(in) (in)

Depth probe

Measure

Inside Vernier Retainer Main scale depths

jaws scale Block (cm)

Measure (cm) movable

internal parts

diameter/ Measurements

thickness

of an object

Reading from main scale : 3.2 cm

Reading from main Vernier scale : 0.04 cm

Reading of Vernier caliper : 3.24 cm 14

0 1 Main Scale

cm

Vernier Scale

No zero error 0 5 10

Negative zero error Positive zero error

0 1 0 1

Main Scale Main Scale

Vernier Scale Vernier Scale

0 5 10 0 5 10

Sixth mark on the Vernier scale is in line with Sixth mark on the Vernier scale is in line with

a mark on the main scale a mark on the main scale

Negative zero error Positive zero error

= - 0.04 cm = +0.06 cm

15

Try this !!!

1. Write down the readings shown by vernier calipers in the following figures:

a) 0 1 b) 0 1

0 5 10 0 5 10

+0.03 cm - 0.06 cm

c) 0 1 d) 0 1

0 5 10 0 5 10

+0.01 cm - 0.03 cm

16

The object which to be The thimble is

measured is placed turned until its jaw

between the jaws (spindle). touches the object.

The ratchet knob

prevents

overtightening by

making a click

sound when the

micrometer is ready

to be read.

MICROMETER SCREW GAUGE

Reading of the main scale

= 4.00 mm

main scale Reading of the thimble scale

Horizontal Vernier = 0.44 mm

reference scale Diameter of ball bearing

line

= 4.44 mm

17

No Zero Error

10

0

Horizontal 5

reference 0 0 mark

line 45

40

Positive zero error Negative zero error

0 10 0 5

Horizontal 5 Horizontal 0

reference 0 2 nd mark reference 45 3 th mark

line 45 above 0 line 40 below 0

Positive zero error = + 0.02 mm Negative zero error = - 0.03 mm

To elliminate the zero error ***

Correct Reading = Reading Obtained − Zero Error

18

Latihan 3.4

1. Write down the readings shown Vernier calipers in the following figures:

a) 3 4 b) 6 7

0 5 10 2.96 cm 6.66 cm 0 5 10

c) 2 3 d) 1 2

0 5 10 2.12 cm 0 5 10 1.11 cm

2. Write down the readings shown by the following micrometer screw gauges.

a) b)

0 25 0 5

20

20 15

15

4.71 mm 9.17 mm

19

3. The following diagram shows the scale of a vernier callipers when the jaws are closed.

0 1 5 6

- 0.04 cm 5.64 cm

0 5 10 0 5 10

(a) (b)

The following diagram shows the scale of the same vernier callipers when there are 50

pieces of cardboard between the jaws. Determine the thickness of one piece of cardboard.

Zero error : - 0.04 cm

Reading of Vernier caliper : 5.64 cm

Thickness of 50 cardboards : 5.64 cm – (-0.04 cm)

= 5.68 cm

Thickness of 1 cardboard : 5.68 cm / 50

= 0.1136 cm

20

Sensitivity & Accuracy of Measuring Instruments

Ammeter Voltmeter

Digital Stopwatch

A V

Metre Rule

20 30

Mercury

Bulb Thermometer 21

Mercury column

Instrument Sensitivity Accuracy

Metre Rule 0.1cm 0.1cm

Vernier Calliper 0.01 cm 0.01 cm

Micrometer Screw Gauge 0.001cm /0.01mm 0.001cm /0.01mm

Ammeter (0 – 5 A) 0.1 A 0.1 A

Miliammeter (0 – 50 mA) 1 mA 1 mA

o

o

Thermometer (-10 ºC – 110 ºC) 1 C 1 C

Mechanical stopwatch 0.2 s 0.2 s

Digital stopwatch 0.01s 0.01s

Miliammeter

Mechanical

Stopwatch

22

1.5 Scientific Investigation

Identifying the problems/ questions /

Identifying the problems/ questions / 1 situations

situations

The problem is identified and stated by asking

question. The problem is usually arised from

an observation

Identifying the variables involve

The question asked must be one that can be

solved experimentally.

Forming a Hypothesis

2 Identifying the variables involve

Manipulated variable

Design and Carry out an experiment ______________________________

The quantity whose values we deliberately

choose to change or a primary variable which

causes other secondary variable to change.

Recording and Presenting data

Responding variable

________________________________

The quantity whose value depend on the

manipulated variable or a secondary variable

Analysing and Interpreting data which changes in response to the change in

the manipulated variable.

________________________________

Constant variable

Making conclusion The quantity whose value is kept constant

throughout the experiment.

Writing a Report 23

3 Form A Hypothesis 4 Design and Carry out an experiment

A general statement about the relationship Aim

between a manipulated variable and a

responding variable. A statement to show the investigation of

The hypothesis should be written as : the variables involve. The aim of the

experiment should be written as:

To investigate the relationship between

The greater the………, the greater the…….

………..and ………………

or

Apparatus

List the apparatus and materials used so

The bigger the…………, the smaller the…..

that at least a set of data for manipulated

and responding variables can be

determined. State the arrangement of the

apparatus that can function by drawing a

labeling diagram.

Procedure

1. State the method of controlling the

manipulated variables

2. State the method of measuring the

responding variables

3. Repeat the experiments at least four

times.

24

5 Recording and Presenting data 7 Making conclusion

When the data is organised in a table, it is Based on the analysis and data

easier to analyse than recorded interpretation, make a rational conclusion

randomly.

8 Writing a Report

6 Analysing and Interpreting data Report must be written after the scientific

investigation is completed.

Plot a graph of ( Responding variable)

against (Manipulated variable) The report must consist of aim, problem

statement, hypothesis, variables,

apparatus and material, procedure,

How to analyze the data ?

(a) Determine the relationship between result, discussion and conclusion.

two variables.

(b) Determine the gradient of the graph

25

Relationship between two variables

a a a

a ∝ F a ∝ 1 a ∝ 1

m m

1

F m

0 0 0 m

a is directly a is inversely 1

proportional to F proportional to m a is directly proportional to m

y y

x x

0 0

y increasing linearly y decreasing linearly with

with x x

26

Revision Questions

C. F D. F

1. Which of the following force-compression

graphs shows that the compression,x of a

spring is directly proportional with the force

that is applied, F? x x

3.

A. F B. F

P

x x 10

C. F D. F

Q

5

x x The equation of the graph above is

A) P = 10Q + 5 B) P = 2Q + 10

2. Which of the following is the best graph ?

C) P = – 2Q + 10 D) P = 5Q – 10

A. F B. F

x x

27

4. Table shows the readings of the length of a rod as recorded by two students, X and Y

Reading of student X/cm Reading of student Y/cm

2.42 2.43

2.38 2.41

2.40 2.38

2.36 2.34

a) What was the instrument used by both students?

b) Why four readings were taken for each measurement?

c) What is the average value of the readings made by

i) student X ?

ii) student Y ?

d) Which set of reading is more accurate? Why?

e) Apart from the instrument in (a), what instruments can be used although they are

less accurate?

Answers :

a) Vernier caliper

b) To increase the accuracy

c) (i) student X (ii) student Y ?

. 2 42 . 2 38 . 2 40 . 2 36 . 2 39 cm . 2 43 . 2 41 . 2 38 . 2 34 . 2 39 cm

4 4

d) Both are same accurate. Their average readings are the same.

e) Meter ruler 28

5.

Load Time for 10 Period of T /s 2 W/T N s -2

2

2

W/N oscillations, t/s oscillation, T/s

1.0 6.7 0.67 0.449 2.228

2.0 9.5 0.95 0.903 2.216

3.0 11.6 1.16 1.346 2.229

4.0 13.4 1.34 1.796 2.228

The above table shows the experimental data that is obtained by a student using the

weighted spring oscillation system.

a) Name the variable that is manipulated.

b) Name the variable that responds.

c) Complete the above table with the corresponding values.

2

d) State the derived unit for W/T .

2

e) Draw the graph of T against W.

f) Interpret the shape of the graph that you have drawn.

g) Calculate the gradient of your graph.

h) Write relationship between the load and the period.

Answers :

a) Weight of load, W

b) Period of oscillation, T

-3

d) kgms / N s -2

f) A straight line originated from 0 and with positive gradient.

g) 0.453 N s

-1 2

2

h) T directly proportional with W 29

1 T / s 2

2

2.0

7 6

1.8

1.6

5 W/N T /s 2

2

1.4 1.0 0.45

2.0 0.90

3.0 1.35

1.2 4.0 1.80

1.0

6 . 1 4 . 0

m . 0 453

0.8 5 . 3 . 0 85

0.6

0.4

4

0.2

3 2

W / N

0 1 2 3 4 30