chapter 1 introduction to physics (teacher' guide)

Physics Module Form 4

Teacher’s Guide Chapter 1 : Introduction To Physics

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CHAPTER 1 : INTRODUCTION TO PHYSICS

1.1 Understanding Physics

Mechanical Energy

PHYSICS

Study of the natural phenomena and the

properties of matter.

Solid

Liquid

Gas

Mechanical Energy

Heat Energy

Light Energy

Wave Energy

Electrical Energy

Nuclear Energy

Chemical Energy

Relationship

with

matter

Properties of

Energy

Relationship

with

energy

Properties of

Matter

forms states

Matter Energy

Mechanics

Properties

of matter

Heat

Light

Wave

in the fields

of

Electricity &

Electromagnetism Atomic Physics

& Nuclear

Physics

Electronics



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1.2 PHYSICAL QUANTITIES

Base quantity

1 A physical quantity is ……………………………………………………………………..

2 Examples of scientific instruments :………………………………………………………

3 A base quantity is a physical quantity which cannot be defined in terms of other physical

quantities.

4 Study the following picture and list the physical quantities that can be measured.

5 List of 5 basic physical quantities and their units.

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

Length

Mass

Time

Current

Temperature

6 Two quantities that have also identified as basic quantity. There are :

i) …………………………..unit …………..

ii) ………………………. unit ……………..

The list of physical quantities :

1. ……………………………………….

2. ……………………………………….

3. ……………………………………….

4. ……………………………………….

5. ……………………………………….

6. ……………………………………….

7. ……………………………………….

8. ……………………………………….

any quantity that can be measured by a scientific instrument.

stopwatch, metre rule balance,thermometer,ammeter

etc.

Height,

mass,

size,

age,

temperature,

current

Power,

Thermal energy

l meter m

m kilogram kg

t second s

I Ampere A

T Kelvin K

Light intensity candela

Amount of substance mol



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Standard Form

1 Standard form = A x 10n , 1 ≤ A < 10 and n = integer no.

2 Standard form is used to …………………………………………………………………...

3 Some physical quantities have extremely small magnitudes. Write the following

quantities in standard form :

a. Radius of the earth = 6 370 000 m =………………………………………………….

b. Mass of an electron = 0.000000000000000000000000000000 911 kg =………...

c. Size of a particle = 0.000 03 m = ………………………………………………………

b. Diameter of an atom = 0.000 000 072 m = …………………………………………...

c. Wavelength of light = 0.000 000 55 m = ……………………………………………..

Prefixes

1. Prefixes are usually used to ………………………………………………………………...

2. It will be written ……………………………………………………………………………

3. The list of prefixes :

Tera (T)

Giga (G)

Mega (M) kilo (k)

mili (m)

micro ()

nano (n)

pico (p)

1012

10

9

10

6

10

3

10

0

10

-3

10

-6

10

-9

10

-12

Hekto (ha) Deka (da)

desi (d) centi (s)

102

101

10-1

10

-2

Eg :

1 Tm = …………………………………….

3.6 mA = …………………………………….

How to change the unit ;

Eg :

1. Mega to nano

2. Tera to micro

3. piko to Mega

simplify the expression of very large and small numbers

6.37 x 106 m

1.673 x 10-27

kg

3.0 x 10-4

m

7.2 x 10-8

m

5.5 x 10-7

represent a large physical quantity or extremely small quantity in S.I

units.

before the unit as a multiplying factor.

1 x 1012

m

3.6 x 10-3

A

1.33 MA = 1.33 x 106 A

= 1.33 x 10 6-(-9)

nA

= 1.33 x 10 15

nA

1.23 Tm to unit m unit

1.23 Tm = 1.23 x 10 12

m

= 1.23 x 10 12 – (-6)

m

= 1.23 x 10 18

m

5456 pA to MA unit

5456 pA = 5.456 x 10 3 + (-12)

pA

= 5.456 x 10 -9

pA

= 5.456 x 10 -9 –(6)

MA

= 5.456 x 10 -15

MA



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4. Some physical quantities have extremely large magnitudes. These extremely large and

small values can be written in standard form or using standard prefixes. Write the

quantities in standard prefixes:

a. Frequency of radio wave = 91 000 000 Hz = ………………………………………….

b. Diameter of the earth = 12 800 000 m = ………………………………………………

c. Distance between the moon and the earth = 383 000 000 m = ………………………

d. Mass of the earth = 6 000 000 000 000 000 000 000 000 kg = ………………………

Derived quantities

1 A derived quantity is …….…………………………………………………………………

………………………………………………………………………………………………

2 Determine the derived unit for the following derived quantities.

Derived

quantity Formula Derived unit

Name of

derived unit

area area = length x width m x m = m2

–

volume volume = length x width x height m x m x m = m3

–

density volume

massensityd

3

3mkg

m

kg –

velocity time

ntdisplaceme elocityv 1sm

s

m –

momentum momentum = mass x velocity kg m s-1

–

Acceleration time

velocityinchangeonaccelerati

2

11-1

sm

ssms

sm

–

Force force = mass x acceleration kg m s-2

Newton (N)

pressure area

force pressure

weight weight = mass x gravitational acceleration

work work = force x displacement

power time

workpower

kinetic energy 2velocitymassK.E

2

1

kg m s-2

/ m2 kg m

-1 s

-2

(Nm-2

)

kg ms -2

Newton (N)

N m Joule (J)

J s -1

Watt (W)

Kg ms-2

Joule (J)

9.1 x 101

MHz

12.8 Mm = 1.28 x 10 1 Mm

383 Mm = 3.83 x 10 2 Mm

6.0 x 10 12

Tm

a physical quantity which combines several basic quantities

through multiplication, division or both



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Derived

quantity Formula Derived unit

Name of

derived unit

potential

energy P.E = mass x gravitational acceleration x height Kg ms

-2 Joule (J)

charge charge = current x time Ampere second

(As) Coulomb (C)

voltage charge

workvoltage J C

-1 Volt (v)

resistance current

voltageresistance v A

-1 Ohm (Ω)

Note that the physical quantities such as width, thickness, height, distance, displacement,

perimeter, radius and diameter are equivalent to length.

1.3 SCALAR AND VECTOR QUANTITIES

1 Scalar quantities are ………………………………………………………………………

Examples : …………………………………………………………………………………

2 Vector quantities are………………………………………………………………………...

Examples : …………………………………………………………………………………

3 Study the following description of events carefully and then decide which events require

magnitude, direction or both to specify them.

Description of events Magnitude Direction

1. The temperature in the room is 25 0C

2. The location of Ayer Hitam is 60 km to the

north-west of Johor Bahru

3. The power of the electric bulb is 80 W

4. A car is travelling at 80 km h-1

from Johor Bahru

to Kuala Lumpur

1.4 MEASUREMENTS

Using Appropriate Instruments to Measure

1 There are various types of………………………………………………………………….

2 We must know how to choose the appropriate instrument to ……………………………..

Quantity which has only magnitude or size

Mass, Length, Speed, volume

Quantity which has magnitude or size and direction.

Velocity, Force, Displacement, Acceleration

Ý

Ý Ý

Ý

Ý Ý

measuring instrument with different measuring capabilities.

measure a particular quantity.



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3 Examples of instrument and its measuring ability.

Measuring instrument Range of measurement Smallest scale division

Measuring tape

Meter rule

Vernier caliper

Micrometer screw gauge

4 Sample of measuring instruments :

4.1 Ammeter : ……………………………………………………………………………..

4.2 Measuring cylinder : ……………………………………………………....................

4.3 Ruler : ………………………………………………………………………………………

wrong right wrong

10 11 12 13 14 15 Reading = ……………… cm

4.4 Vernier calliper

A venier calliper is used to measure :

a. ………………………………………………b. ………………………………………….

c. ………………………………………………d. ………………………………………….

A vernier calliper gives readings to an accuracy of …………………………………...…. cm.

pointer mirror pointer mirror

Pointer’s image is behind the pointer

incorret reading correct

reading

1 2 3 0 4

1 2 3 0 4

Pointer’s image can be seen

Right position of eye (eye are in a line perpendicular to the plane

of the scale)

wrong position of eye

wrong position of eye

water

is use to determine the volume of liquid.

is use to determine the length

2.5 cm

small object depth of a hole

external diameter of a cylinder or pipe internal diameter of a pipe or tube

0.01cm

Up to a few meters 0.1 cm

1 m 0.1 cm (0.01 m)

10 cm 0.01 cm

less than 2 cm (20 mm) 0.001 cm (0.01 mm)

is use to measure electric current



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Length of vernier scale = ……… cm

Vernier scale is divided into 10 divisions

Length of the divisions = ………. cm

The diagram below shows a vernier calliper with reading.

Vernier calliper reading = ……………. cm

4.5 Micrometer screw gauge.

A micrometer screw gauge is used to measure :

a. ………………………………………………

b. ………………………………………….

c. ………………………………………………

0 5 10

0 1

0 1

0 5 10

Main scale in cm

Vernier scale

cm 0 1 2 3 4 SKALA

UTAMA 0

5 10

inside jaws Vernier scale

outside jaws

Main scale

0 1 2 3 4 5 6 7 8 9 10

0 1 cm

Main scale = ………………….

Vernier scale = …………………..

Final reading = …………………..

Find the division of vernier scale which is coincides with any part of the main scale

Anvil spindle sleeve (main scale) thimble (circular scale) ratchet frame

One complete turn of the thimble

(50 division) moves the spindle by

0.50 mm.

Division of thimble

= …………………..

= …………………..

A accuracy of micrometer

screw gauge = ……………..

Sleeve scale : ……………

Thimble scale : ………….

Total reading : …………..

The differenct between the main scale and vernier

scale is = ……………………………. cm

0.15

objects that are small in size

diameter of a wire

diameter of small spheres such as ball bearings

0.5 ÷ 50

0.01 mm 4.5 mm

0.01 mm 0.22 mm

4.62 mm

1.0

0.01

0.01 cm

0.2 cm

0.06 cm

0.26 cm



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Example :

4.6 Some others measuring instruments :

……………………… …………………… ……………………… ………..

………………………. …………………….. ………………

Hands-on activity 1.1 on page 1 of the practical book to learn more about choosing

appropriate instruments.

Exercise: Vernier Callipers And Micrometer Screw Gauge

1. Write down the readings shown by the following

(a)

(b)

Sleeve scale : ……………

Thimble scale : ………….

Total reading : …………...

0 5 10

7 8

0 5 10

4 5 A B

Q P

Answer: …7.89 cm…………..

Answer: …4.27 cm…………..

2.0 mm

0.22 mm

2.22 mm

Analogue stopwatch digital stopwatch thermometer miliammeter

Measuring tape measuring cylinder beaker



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(c)

(d)

2. (a) The following diagram shows the scale of a vernier calliper when the jaws are closed.

Zero error = …0.02……… cm

(b). The following diagram shows the scale of the same vernier calliper when there are

40 pieces of cardboard between the jaws.

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

(a) (b)

Answer: ………6.87 cm……… Answer:……12.32 cm…………..

0 5 10

0 1

0 5 1

0

6 7

0 5 10

5 6

0 5 10

0 1

Answer: ……6.28 cm………..

Answer: …0.02 cm…………..

Reading shown = …5.64…….cm

Corrected reading = …5.62……..cm

35

40 0 5

30

0 5 10 35



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(c) (d)

Answer:………4.71 cm………………… Answer:……9.17 cm………

4. (a) Determine the readings of the following micrometer screw gauges.

Zero error = …- 0.02…….. mm Zero error = …+0.03…….. mm

(b) Determine the readings of the following micrometer screw gauges.

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

(a) (b)

Answer: …6.88 mm………… Answer: …..12.32 mm……

(c) (d)

Answer:………4.71 mm………… Answer: 9.17 mm…………

20

25 0

0 0

45

5

0

0

5

0

0 0 5

15

20

15

20 0 5

Zero error = +0.03………mm Reading shown = 6.67………..mm

Corrected reading = 6.64………..mm

35

40 0 5

30

0 5 10 35

20

25 0

15

20 0 5



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Accuracy and consistency in measurements.

1. Accuracy : …………………………………………………………………………………

2. Consistency : ………………………………………………………………………………

3. Sensitivity : …………………………………………………………………………………

………………………… ……………………… ……………………………..

…………………….. …………………………….. ………………………………

Hands-on activity 1.2 on page 2 of the practical book to determine the sensitivity of

some measuring instruments.

Errors in measurements

1. All measurements are values ………………………………………………………………

2. In other word, it is a matter of ……………………………………………………………

3. This is because ……………………………………………………………………………

4. Two main types of errors:

4.1 ……………………………………………

Occurs due to :

a) ………………………………………………………………………………………

b) ………………………………………………………………………………………

c) ………………………………………………………………………………………

Examples :

a) ………………………………………………………………………………………

b) ………………………………………………………………………………………

c) ………………………………………………………………………………………

target

target

The ability of an instrument to measure nearest to the actual value

The ability of an instrument to measure consistently with little or no relative

deviation among readings.

The ability of an instrument to detect a small change in the quantity measured.

consistent but inaccurate consistent and accurate inaccurate and not consistent

Accurate but not consistent inaccurate but consistent inaccurate but not consistent

of approximation only.

how close the measurement is to the actual value.

error exist in all measurements.

Systematic errors

a weakness of the instrument

the difference between reaction time of the brain and the action.

zero error is when the pointer is not at zero when not in use.

Range of the measuring instrument – absolute error .

Reaction time of the brain.

Initial reading is not at the zero scale – zero error



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Absolute error :

……………………………………………………………………………………….…………

………………………………………………………………………………………………….

Zero error : …………………………………………………………………………………...

Correct reading = observed reading – zero error

4.2 ……………………………………………..

Occurs due to

a) ………………………………………………………………………………………

b) ………………………………………………………………………………………

c) ………………………………………………………………………………………

Example :

a) Readings are close to the actual value but they are not consistent.

Can be minimized by consistently repeating the measurement at different places in an

identical manner.

Parallax error :

Example :

Zero error of screw meter gauge

Positive zero error

Horizontal

reference

Horizontal

reference 3 divisions above

horizontal reference 2 divisions below

horizontal reference

Zero error = - 0.02 mm

Refer to the smallest reading that can be measured by an instrument.

If, the smallest reading = 0.1 cm

Then, Absolute error = 0.1 / 2 = 0.05 cm

where the pointer is not at zero when not in used

+0.03 cm - 0.04 cm

Positive zero error Negative zero error

Random error

carelessness in making the measurement.

parallex error , incorrect positioning of the eye when taking the readings.

sudden change of ambient factors such as temperature or air circulation.

It occurs because the position of the eye is not perpendicular to the scale of the instrument

wrong

right position of the eye (no error)

wrong

Positive zero error

Zero error = +0.03

Zero error =

0 1 cm

0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10

Zero error =

0 1 cm



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1.5 SCIENCETIFIC INVESTIGATION

Steps Explanation

1 Making

observation

Gather all available information about the object or phenomenon

to be studied.

Using the five senses, sight, hearing, touch, taste and smell.

2 Drawing

inferences

A conclusion from an observation or phenomena using

information that already exist.

3

Identifying

and controlling

variables

Variables are factors or physical quantities which change in the

course of a scientific investigation.

There are three variables :

i. Manipulated variables

- physical quantity which change according to the aim

of the experiment.

ii. Responding variables

- physical quantity which is the result of the changed

by manipulated variable.

iii. Fixed variables

physical quantities which are kept constant during the experiment.

4 Formulating a

hypothesis

Statement of relationship between the manipulated variable and

the responding variable those we would expect.

Hypothesis can either be true or false.

5 Conducting

experiments

i. Conduct an experiment includes the compilation and

interpretation of data.

ii. Making a conclusion regarding the validity of the hypothesis.

Plan and report an experiment

Situation : A few children are playing on a different length of swing in a

playground. It is found that the time of oscillation for each swing is different.

Steps Example : refer to the situation above

1 Inference

2 Hypothesis

3 Aim

The period of the oscillation depends on the length of the

pendulum.

When the length of the pendulum increases, the period of the

oscillation increases.

Investigate the relationship between length and period of a

simple pendulum.



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4 Variables

Manipulated variable : the length of the pendulum.

Responding variable : Period

Fixed variable : the mass of the pendulum and the

displacement.

5 List of

apparatus and

materials

Retort stand with clamp, 100 cm of thread, bob,

meter rule, 2 blocks of clamp wood, protractor and

stop watch.

6 Arrangement of

the apparatus

7 Procedures

8 Tabulate the

data

l

1. Set up the apparatus as shown in the figure above. 2. Measure the length of the pendulum,l = 60.0 cm by using a meter

rule. 3. Give the pendulum bob a small displacement 300.Time of 10 oscillations is measured by using a stop watch. 4. Repeat the timing for another 10 oscillations. Calculate the

average time. Period = t10 oscillations 10 5. Repeat steps 2, 3 and 4 using l = 50.0 cm, 40.0 cm, 30.0 cm and 20.0 cm

11..5588

11..5500

11..3311

11..1199

00..9999

1155..88

1155..00

1133..11

1111..99 99..99

1155..77

1155..00

1133..11

1111..99 99..99

1155..88

1155..00

1133..11

1111..99 99..99

6600..00

5500..00

4400..00

3300..00

2200..00

PPeerriioodd// ss

((TT == tt1100//1100)) AAvveerraaggee 22 11 LLeennggtthh,,ll //

ccmm

Time for 10 oscillations / s

Retort stand protractor

l

bob



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9

10

11

Analyse the

data

Discussion

Conclusion

Reinforcement Chapter 1

Part A :Objective Question

1. Which of the following is a base SI

quantity?

A Weight B Energy

C Velocity D Mass

2. Which of the following is a derived

quantity?

A Length B Mass

C Temperature D Voltage

3. Which of the following is not a basic

unit?

A Newton B kilogram

C ampere D second

4. Which of the following quantities

cannot be derived?

A Electric current B Power

C Momentum D Force

5. Which of the following quantities is

not derived from the basic physical

quantity of length?

A Electric charge B Density

C Velocity D Volume

T / s 1.4

1.2 1.0 0.8 0.6 0.4 0.2

Graf of period, T vs pendulum’s length, l

0 10 20 30 40 50 60 l / cm

Precautions : 1. Oscillation time is measured when the pendulum attained a

steady state. 2. Time for 10 oscillations is repeated twice to increase accuracy. 3. Discussion (refer to given questions) The period increases when the length of the pendulum increases. Hypothesis accepted.



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6. Initial velocity u, final velocity v,

time t and another physical quantity k

is related by the equation v - u = kt.

The unit for k is

A m s-1

B m-1

s

C m s-2

D m2 s

-2

7. Which of the following has the

smallest magnitude?

A megametre B centimetre

C kilometre D mikrometre

8. 4 328 000 000 mm in standard form is

A 4.328 x 10-9

m B 4.328 x 10-6

m

C 4.328 x 106 m D 4.328 x 10

9 m

9. Which of the following measurements

is the longest?

A 1.2 x 10-5

cm B 120 x 10-4

dm

C 0.12 mm D 1.2 x 10-11

km

10. The diameter of a particle is 250 m.

What is its diameter in cm?

A 2.5 x 10-2

B 2.5 x 10-4

C 2.5 x 10-6

D 2.5 x 10-8

11. Which of the following prefixes is

arranged in ascending order?

A mili, senti, mikro, desi

B mikro, mili, senti, desi C mili, mikro, desi, senti

D desi, mikro, mili, senti

12. Velocity, density, force and energy are

A basic quantities

B scalar quantities

C derived quantities D vector quantities

13. Which of the following shows the

correct conversion of units?

A 24 mm3 =2.4 x 10

-6 m

3

B 300 mm3=3.0 x 10

-7 m

3

C 800 mm3=8.0 x 10

-2 m

3

D 1 000 mm3=1.0 x 10

-4 m

3

14. Which of the following measurements

is the shortest ?

A 3.45 x 103 m

B 3.45 x 104 cm

C 3.45 x 107 mm

D 3.45 x 1012

m

15. The Hitz FM channel broadcasts radio

waves at a frequency of 92.8 MHz in

the north region. What is the frequency

of the radio wave in Hz?

A 9.28 x 104 B 9.28 x 10

5

C 9.28 x 107 D 9.28 x 10

10

16. An object moves along a straight line

for time, t. The length of the line, s is

given by the equation 2

2

1gts . The

SI unit of g is

A m2 s

2 B m s

-2

C s-1

D s-2

m



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Part B : Structure Question

1. A car moves with an average speed of 75 km h-1

from town P to town Q in 2 hours as

shown in Figure 1. By using this information, you may calculate the distance between the

two towns.

P Q

Figure 1

(a) (i) Based on the statements given, state two basic quantities and their respective

SI units.

………………………………………………………………………………………

(ii) State a derived quantity and its SI unit.

………………………………………………………………………………………

(b) Convert the value 1 . m to standard form.

5 x 10-3

(c) Complete Table 1 by writing the value of each given prefix.

Table 1

(d) Power is defined as the rate of change of work done. Derive the unit for power in

terms of its basic units.

(e) Calculate the volume of a wooden block with dimension of 7 cm, 5 cm breadth and 12

cm height in m3 and convert its value in standard form.

Distance : m and time : s

Speed – m s-1

= 0.2 x 103 m

= 2.0 x 102 m

10

-9

10-6

106

109

Power =time

work =

time

ntdisplacemeForce Unit =

s

mkgms 2

= kg m2 s

-3

Volume = (7 x 10

-2) (5 x 10

-2) (12 x 10

-2)

= 420 x 10-6

= 4.20 x 10

-4 m

3



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2. Figure 2 shows an ammeter of 0—3 A range.

Figure 2

(a) (i) Name component X. ………………………………………………………………...

(ii) What is the function of X? ………………………………………………………….

(b) Table 2 shows three current readings obtained by three students.

Table 2

(i) Did all the students use the ammeter in Figure2? ..………………………………….

(ii) Explain your answer in (b)(i).

………………………………………………………………………………………

3. Figure 3 shows the meniscus of water in a measuring cylinder K, L, and M are three eye

positions while measuring the volume of the water.

(a) (i) Which of the eye positions is

correct while taking the reading of the

volume of water?

…….……………………………………

Figure 3

(b) The water in the measuring cylinder is

replaced with 30 cm3

of mercury.

(i) In Figure 4, draw the meniscus of the

mercury in the measuring cylinder. Figure 4

(ii) Explain why the shape of the meniscus of mercury is as drawn in (b)(i).

……………………………………………

No

3rd

readings obtained by student 2 and 3 are out of the meter range.

L

The cohesive force is larger than the adhesive force

Mirror

To avoid parallax error

chapter 1 introduction to physics (teacher' guide)

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