Introduction to Physics

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