1.0 understanding physics

Physics Module Form 4 Chapter 1 – Introduction to physics GCKL 2011

1.1
U N D E R S T A N D I N G P H Y S I C S

Recognise the 1. Tick () the statements that are related to physics.
concepts of
Blood circulation in our body is controlled by heart.
physics in
everyday objects
A large truck moves faster than a car because it has a more powerful engine.
and natural We need water in our digestion system.
phenomena Orange juice is acidic because its taste is sour.
An object on a high building has a large potential energy.
When we heat water, its temperature increased.
We are sweating when our body metabolism is high.
Pure water has pH 7.
We cannot see object in dark
A ship is floating in water.
Human body coordination is controlled by hormone system.
Oxidation will act faster in acidic medium.

1.2
UNDERSTANDING BASE AND DERIVED QUANTITIES

Recognise 1. Identify Physical quantities, Magnitude, Units and Measuring instrument from the
physical quantity statements below. Write them into the table below (next page).
and unit
A
Ismail weigh a wooden block that has mass of 500 gram using a lever beam balance.
B Ong Beng Hock measures the length of a building which is 100 meter long using a
measuring tape.
C Siew Mei measures her body’s temperature using a digital thermometer and obtains
38C.
D Bathumalai determines the volume of water using a measuring cylinder and obtains
150 milliliter.
E Hanisah measures the diameter of a wire which is 1.26 millimeter using a
micrometer screw gauge.
F Vinisha takes the time of 20 oscillations of a pendulum using a stopwatch and
obtains 24.6 seconds.

Measuring
Statement Physical quantity Magnitude Unit
instrument
A

B

C

D

E

F

1-1


Define base 2. Identify base quantities and derived quantity from the equation below.
quantities and
derived quantities (a) Volume = length x length x length
are
Base quantity = (i) _________________

Derived quantity = (i) _________________

(b) Area = length x length

Base quantity = (i) _________________


(c)

Base quantity = (i) _________________ (ii) ____________________


(i) Base quantity is physical quantity that __________ be derived from any quantities.

(ii) Derived quantity is physical quantity that ___________________ from the base
quantities.
List base quantities
and their S.I unit PHYSICAL QUANTITY S.I UNIT
Pressure Time Current Second Newton Ampere
Length Area Temperature Kelvin kilogram Pascal
Weight Force Volume Joule m2 Watt
Work Energy Power m s-1 meter m3
Velocity Mass

3. Choose base quantities from the physical quantities given above and state their S.I
units.

No. Base Quantity S.I Unit
1.

2.

3.

4.

5.

1-2


List some derived 4. Write 5 derived quantities from physical quantities given in the box above (previous
quantities and their page) and state their S.I units.
S.I units
No. Derived Quantity S.I Unit
1.
2.
3.
4.
5.

Express quantities 5. Rewrite the values below in scientific notation (Standard notation)
using scientific
notation No. Original value Scientific notation
1. 12 000 m
2. 3 000 000 000 s
3. 0.000 000 000 56 N
4. 0.000 78 J
5. 0.0034 A

Express quantities 6. Arrange the prefixes given below in ascending order. Then, state their multiple / sub-
using prefixes multiple.

PREFIXES MULTIPLE / SUB-MULTIPLE
Nano (n) kilo (k) pico (p) 103 109 10-2
1
mega (M) centi (c) giga (G) 10 10-12 106
deci (d) deca (da) tera (T) 10-6 102 10-1
-9
hector (h) micro () milli (m) 10 10-3 1012

Multiple / Multiple /
No. Prefix No. Prefix
Sub-multiple Sub-multiple
1. 7.
2. 8.
3. 9.
4. 10.
5. 11.
6. 12.

Solving problem 1. Rewrite the values below using the suitable prefix.
involving
conversion of units (i) 4.1 x 1012 m = __________ (vii) 3.8 x 102 K = __________
1 9
(ii) 9.3 x 10 s = __________ (viii) 1.7 x 10 W = __________
(iii) 0.5 x 10-3 J = __________ (ix) 4.1 x 103 C = __________
(iv) 11.2 x 10-2 N = __________ (x) 9.5 x 10-6 A = __________
6 -12
(v) 5.9 x 10 V = __________ (xi) 8.6 x 10 m = __________
-9 -1
(vi) 6.6 x 10 m = __________ (xii) 2.2 x 10 s = __________

1-3


2. Replaced the prefix in the values below with the correct multiple or sub-multiple.

(i) 4.1Tm = __________ (vii) 3.8 daK = __________
(ii) 9.3 ms = __________ (viii) 1.7 GW = __________
(iii) 0.5 kJ = __________ (ix) 4.1 hC = __________
(iv) 11.2 cN = __________ (x) 9.5 A = __________
(v) 5.9 MV = __________ (xi) 8.6 pm = __________
(vi) 6.6 dm = __________ (xii) 2.2 ns = __________

Check Yourself 1

1. Which physical quantity has the correct S.I 5. Which of the following physical quantities is
unit? not a base quantity?

Physical quantity S.I unit A Weight C Temperature
B Time D Electric current
A Temperature Celcius
B Time minute
C Mass Newton 6. A radio station airs its programmes by
D Length metre transmitting waves at a frequency of
102.3 MHz. How much is this frequency, in
Hz?
2. Time, speed, density, and energy are ..............
quantities. A 1.023 x 102
B 1.023 x 105
A base C vector C 1.023 x 106
B scalar D derived D 1.023 x 108

3. Which of the following shows the correct 7. Which of the following values is equal to 470
relationship between the base quantities for pF?
density?
A 4.7 x 10-10 F
B 4.7 x 1011 F
A
C 4.7 x 10-7 F
D 4.7 x 102 F
B
8. Hamid cycles at a velocity of 3.1 km h-1.
What is this velocity, in m s-1?
C
A 0.09 C 1.16
B 0.86 D 11.61
D

9. Which measurement is the longest?
4. Which of the following is not a base S.I unit?
A 2.68 x 103 m
A Gram C Ampere B 2.68 x 10-1 mm
B Kelvin D Meter C 2.68 x 103 cm
D 2.68 x 10-4 m
1-4


10. Which of the following conversion of unit is 11. Which of the following frequencies is the
correct? same as 106.8 MHz?

A 24 mm3 = 2.4 x 10-6 m3 A 1.068 x 10-4 Hz
B 300 mm3 = 3.0 x 10-7 m3 B 1.068 x 10-1 Hz
C 800 mm3 = 8.0 x 10-2 m3 C 1.068 x 102 Hz
D 1 000 mm3 = 1.0 x 10-4 m3 D 1.068 x 106 Hz
E 1.068 x 108 Hz

1.
UNDERSTANDING SCALAR AND VECTOR QUANTITIES
3
Define scalar and 1. Read the statements below to make a generalisation on scalar quantity and vector
vector quantities. quantity. Then classify the physical quantities into scalar quantity and vector quantity
in the table below.

A Hasan walks with a velocity of 2 m s-1 due West.
B Husna runs with a speed of 5 m s-1.

C Sangeetha walks along a displacement of 40 m due North.

D Jason runs along a distance of 30 m.

E Chin Wen push the table downwards with a force of 30 N.

F Wen Dee has a mass of 40 kg.

Scalar Quantity Vector Quantity

(i) Scalar quantity is physical quantity that has _______________________.

(ii) Vector quantity is physical quantity that has _______________________ and

________________________.

Differentiate 2. Underline the correct physical quantity.
between distance
and displacement. (i) (Distance / Displacement) is the total length travelled by an object.

(ii) (Distance / Displacement) is the shortest length measured between the initial
point and the final point.

1-5


EXAMPLE:

A 4m B
A boy walks from A to C through B.

(i) Distance of the boy =4m+3m =7m
3m

(ii) Displacement of the boy = =5m

C

Check Yourself 2

1. Which of the following quantities is a vector
3. Which quantity is a vector quantity?
quantity?
A Energy C Force A Area C Distance
B Power D Pressure B Length D Displacement

2. Diagram below shows the path travelled by a
4. Which of the following is group of vector
car from P to S.
quantities?
5 km A Velocity, mass, displacement
P Q
B Speed, time, acceleration
C Force, velocity, displacement
3 km D Area, temperature, momentum

S R
1 km

What is the displacement of the car?

A 5.0 km C 8.2 km
B 6.8 km D 9.0 km

1-6


1.4
U N D E R S T A N D I N G M E A S U R E M E N T S

Recognise 1. State the suitable measuring instrument for the physical quantities in the table below.
appropriate
instrument for MEASURING INSTRUMENT
physical quantities Metre rule Barometer Thermometer Lever balance
Spring balance Hydrometer Measuring cylinder Bourdon gauge
Ammeter Voltmeter Stopwatch Vernier calliper
Micrometer screw gauge

No. Physical Quantity Measuring Instrument
1. Temperature
2. Length
3. Time
4. Mass
5. Electric current
6. Voltage
7. Density
8. Atmospheric pressure
9. Pressure
10. Force
11. Volume
12. Diameter of tube
13. Diameter of wire

Measure physical 2. Label the part of vernier calliper below.
quantity using
vernier calliper. PART OF VERNIER CALLIPER
Inner jaws Outer jaws Main scale Vernier scale

0 1 2 3 4 5 6

1-7


3. Take the reading from a vernier calliper:

EXAMPLE:
(i) 0.70
(i) Read the main scale.
cm
Main scale reading = 0.70 cm

0 1 2 (ii) Read the vernier scale.
0 Vernier scale reading = 0.02 cm
(iii) Total up the readings.
(ii) 0.02 Actual reading = 0.72 cm
cm
4. Read the vernier calliper below.

(i) 3 4 (ii) 2 3

0 0

Main scale = .................... Main scale = ....................
Vernier scale = .................... Vernier scale = ....................
Actual reading = .................... Actual reading = ....................

(ii) (iv)
8 9 0 1

0

Main scale = .................... Main scale = ....................
Vernier scale = .................... Vernier scale = ....................
Measure physical 5. Label the part of micrometer screw gauge below.
quantity using
micrometer screw PART OF MICROMETER SCREW GAUGE
gauge. Anvil Spindle Sleeve Thimble Ratchet

1-8


6. Take the reading from a micrometer screw gauge.

EXAMPLE:

(i) 3.00 mm (i) Read the sleeve scale (main scale).
Sleeve scale reading = 3.00 mm

0 50 (ii) Read the thimble scale.
(ii) 0.44 mm Thimble scale reading = 0.44 mm
40

(iii) Total up the readings.
Actual reading = 3.44 mm

7. Read the micrometer screw gauge below:

(i) (ii)

0 30 0
20
20 10

Sleeve scale = .................... Sleeve scale = ....................
Thimble scale = .................... Thimble scale = ....................

(iii) (iv)

0 0
60
20
50
10

Sleeve scale = .................... Sleeve scale = ....................
Thimble scale = .................... Thimble scale = ....................

1-9


Explain sensitivity. 8. Table below shows readings from three instruments J, K, and L that are used in
measuring the mass of a Petri dish.

Instrument J Instrument K Instrument L
20 g 19.4 g 19.42 g

A piece of dried leaf of mass 0.05 g is then put in the Petri dish.

(i) Which instrument is able to detect the small change of the mass? [...............]
(ii) Which instrument is the most sensitive? [................]
(iii) Which instrument has the highest sensitivity? [................]
(iv) Sensitivity of instrument is the capability of the instrument to ...............................

..................................................................................................................................
(v) Which instrument gives reading in the most decimal place? [.................]
(vi) The ...................... the decimal place, the ........................... sensitivity of the
instrument.
Explain accuracy. 9. Table below shows readings from three instruments P, Q, and R that are used in
measuring the length of a wire. The actual length of the wire is 10.0 cm.

Instrument P Instrument Q Instrument R
10.1 cm 10.4 cm 9.6 cm

(i) Which instrument gives the closest reading to the actual length of the wire?
[...............]
(ii) Which instrument gives the most accurate reading? [...............]
(iii) Which instrument has the highest accuracy? [...............]
(iv) Accuracy of instrument is the capability of the instrument to ..................................

...................................................................................................................................
Explain 10. Table below shows four readings from three instruments X, Y, and Z that are used in
consistency measuring the length of a wire. Each instrument repeats the measurement for four
(Precision) times.

Instrument X 10.0 cm 10.1 cm 10.1 cm 10.0 cm
Instrument Y 10.1 cm 10.4 cm 10.2 cm 9.8 cm
Instrument Z 9.8 cm 9.6 cm 9.9 cm 9.5 cm

(i) Which instrument gives readings with the smallest deviation (difference)?
[...............]
(ii) Which instrument gives the most consistence readings? [...............]
(iii) Which instrument has the highest consistency? [...............]
(iv) Consistency of instrument is the capability of the instrument to .............................

...................................................................................................................................
1-10


Explain type of 11. In an experiment, the readings of measurement taken may have slightly difference due
experimental error.
to some mistakes. The difference in the readings is called as .........................................

12. These errors can be caused by the change of environment, human factors or the
deficiency of measuring instrument.

13. Error that is caused by environment and human usually is (constant / changeable)*.

14. Error that is caused by the instrument is always (constant / changeable)*.

15. Type of Error:

Random Error Difference Systematic Error

Cause

Magnitude /
value

Example

Method to
reduce the
error

Check Yourself 3

1. A, B, C, and D shows the shooting marks on a 2. A, B, C, and D show parts of four different
. target. Which marks can explain the concept balance scales. Which balance is the most
of precision of a measurement? sensitive?

A C A C

B D

B D

1-11


3. Diagram below shows the target board in a 7. The diagrams show the scales on a pair of
game. vernier callipers and a metre rule.
Target
board Target

Which result is consistent but not accurate?

A C Vernier calliper Metre rule

Which comparison is correct about the
sensitivity of the vernier callipers and the
metre rule when measuring the thickness of a
B D wire?

Vernier callipers Metre rule
A Low sensitivity Low Sensitivity
B Low sensitivity High sensitivity
C High sensitivity Low sensitivity
4. The diagram shows the scale of a micrometer D High sensitivity High sensitivity
screw gauge.

8. Table below shows the readings of the
thickness of a board which are taken by four
students.

Reading/cm
Student
1 2 3 4
What is the reading of the micrometer? A 2.50 2.50 2.50 2.50
B 2.53 2.53 2.53 2.53
A 7.02 mm C 7.03 mm C 2.52 2.53 2.54 2.53
B 7.52 mm D 7.58 mm D 2.71 2.73 2.74 2.74

Each student made four measurements. If the
5. The diagram shows the scale of a vernier
actual thickness of the board is 2.53 cm,
calliper.
which of the students A, B, C, and D made
the measurements that are accurate but not
consistent?

9. Diagram (a) shows the reading of a vernier
calliper while its jaws are closed. Diagram (b)
shows the reading of the vernier calliper when
What is the reading of the vernier calliper? a metal sheet is placed between the jaws.

A 2.16 cm C 1.86 cm
B 2.06 cm D 1.76 cm

6. Atmospheric pressure can be measured by
using

A hydrometer (a) (b)
B Bourdon gauge and manometer What is the thickness of the metal sheet?
C Bourdon gauge and mercury barometer A 0.46 cm C 0.38 cm
D manometer and mercury barometer B 0.42 cm D 0.32 cm
1-12


10. Four students, A, B, C, and D use a micrometer 14. Which of the following statements is correct
screw gauge, a metre rule, and a vernier about zero error?
calliper to measure the thickness of a board.
Which student records the reading correctly? A Can be reduced by determining average
reading.
Micrometer Metre Vernier B The magnitude of error increases when
screw rule/mm calliper/mm the value of the reading increases.
gauge/mm C Exist either in positive or negative.
D The magnitude of error increases if the
A 11.1 11 11.13 range of scale is large.
B 11.13 11.1 11.128
C 11.128 11.1 11.13
D 11.13 11 11.1
15. Diagram below shows two types of ammeters,
X and Y, that can be used to measure electric
11. The diagram shows the scale of a micrometer current.
screw gauge.

What is the reading of the micrometer?

A 4.95 mm C 4.50 mm
B 4.55 mm D 4.45 mm

12. Which of the following ways can reduce the
parallax error while taking reading of current
from an ammeter?

A Use a higher sensitivity ammeter. (a) Which ammeter is more sensitive?
B Repeat the measurement and calculate
the average reading. ...................................................................
C Take the reading using a magnifying
glass. (b) State one reason for your answer above.
D Use ammeter that has plane mirror
below the pointer. ...................................................................

...................................................................
13. What is the function of the plane mirror under
the pointer in an ammeter? ...................................................................

A To increase the consistency of the
measurement.
B To increase the accuracy of the
measurement.
C To avoid parallax error.
D To prevent zero error.

1-13


16. Figure below shows the scale of an ammeter. (a) The external diameters of the cylinder at
four different places are shown in the
table below.

Relative
External diameter/cm
Mirror deviation/%
2.04 2.05 2.04 2.06 0.37

(i) Why is the external diameter
measured four times?

.............................................................
(a) Name the physical quantity measured by
the ammeter. .............................................................

................................................................... (ii) What is the purpose of calculating the
relative deviation?
(b) What is the value of the smallest division
on the scale? .............................................................

................................................................... .............................................................

(c) State the function of the mirror located .............................................................
under the scale.

................................................................... 18. Figure below shows the meniscus of oil in a
measuring cylinder. P, Q and R are three eye
................................................................... positions while measuring the volume of the
oil.

17. Figure below shows a vernier calliper used to
measure external diameter of a hollow
cylinder.

(a) Which position of the eye is correct while
(b) Name the part labelled X. taking the reading of the volume of oil?

................................................................... ...................................................................

(c) What is the function of X? (b) Give one reason for the answer above.

................................................................... ...................................................................

................................................................... ...................................................................

1-14


19. A student is assigned to measure the thickness (i) What is the zero error of the vernier
of a metal sheet. The student is provided with calliper?
a vernier calliper.
.............................................................
(a) The student uses the vernier calliper to
measure the thickness of the metal sheet. (ii) Calculate the thickness of the metal
Figure (i) shows the scale of the vernier sheet.
calliper while the jaws are closed. Figure
(ii) shows the scale of the vernier calliper
when the metal sheet is put between the
jaws.

(i)

(ii)
Thickness = .................................

1.5
UNDERSTANDING SCIENTIFIC INVESTIGATION

Identify variables 1. Identify and state the variables that can be investigated from the situations below.
in a given situation
EXAMPLE:
The car moves faster when it is pushed harder.

Cause : pushed harder Manipulated variable : Force
Effect : moves faster Responding variable : Speed/Velocity/
Acceleration

Manipulated Responding
No. Situation
variable variable
1. The temperature of smaller block rises
faster when it is heated.
2. The pendulum system with longer string
takes longer time to stop.
3. The loaded lorry is harder to stop than the
empty lorry.
4. The trolley that falls from the higher place
moves faster.
5. The spring becomes longer when it is
pulled harder.

1-15


Making inference 2. Write inference from the given variables.

EXAMPLE:
Manipulated variable : Length Responding variable: Time

Inference : The length affects the time taken.

No. Inference
variable variable
1. Force Acceleration

2. Mass Temperature

3. Force Extension

4. Mass Time

5. Force Pressure

6. Area Pressure

7. Temperature Volume

Form hypothesis. 3. Write hypothesis from the given variables.

EXAMPLE:
Manipulated variable : Length Responding variable: Time
Hypothesis : The longer the length, the longer the time taken.

No. Hypothesis
variable variable

1. Force Acceleration

2. Mass Temperature

3. Force Extension

4. Mass Time

5. Force Pressure

6. Area Pressure

7. Temperature Volume

1-16


Analyse the data. 4. Data obtained from an experiment can be analysed by plotting a line graph.
Manipulated variable is on the x-axis, and responding variable is on the y-axis.
The variables must be stated together with the correct unit.

EXAMPLE:
Time/min

Manipulated variable : Mass
Responding variable : Time

Mass/kg
5. Sketch a graph to analyse the following variables:

(i) Manipulated variable : Force (ii) Manipulated variable : Mass
Responding variable :
Responding variable : Acceleration
Temperature

(iii) Manipulated variable : Force (iv) Manipulated variable : Mass
Responding variable : Extension Responding variable : Time

1-17


(v) Manipulated variable : Force (vi) Manipulated variable : Area
Responding variable : Pressure Responding variable : Pressure

Interpret data to 6. The conclusion of an experiment is made based on the line graph obtained.
draw a conclusion.
EXAMPLE:

Time/min Pressure/Pa

m-2
Mass/kg
Conclusion: Conclusion:
The time is directly proportional The pressure is inversely proportional
to the mass. to the area.

Temperature/C

Time/min

Conclusion:
The temperature is linearly
increasing with the time.

1-18


Interpret data to 7. Write a conclusion based on the line graphs below:
draw a conclusion.
(i) Period2/s2 (ii) Temperature/C

kg-2
Length/cm
........................................................ .............................................................
........................................................ .............................................................
....................................................... .............................................................

(iii) (iv)

Volume/m3 Extension/cm

Pressure/kPa Force/N

........................................................ .............................................................
........................................................ .............................................................
....................................................... .............................................................

1-19


Check Yourself 4

1. Which of the following graphs obeys the A C
equation F = kx, where k is a constant?
.
A C B D

4. Diagram below shows an investigation about
the stretching of a spring. Babies of different
masses are supported by identical springs.

B D

Which of the following variables are correct?
2. Table below shows the results of an experiment
to investigate between load and extension when
Manipulated Responding Constant
a spring is stretched. variable variable variable
Load, F/N 100 150 200 250 300 A Mass of the Length of Diameter of
baby the spring the spring
Extension, B Length of Mass of the Diameter of
1.0 1.5 2.0 2.5 3.0 the spring baby the spring
x/cm
C Diameter of Length of Mass of the
the spring the spring baby
The original length of the spring is l0 = 15.0 cm. D Mass of the Diameter of Length of
What is the manipulated variable? baby the spring the spring
A Load, F
B Extension, x 5. The graph shows the relationship between
C Original length of the spring, l0
physical quantities P and Q.
D Material used to make the spring

3. The graph shows the relationship between v
and t.

Which statements about the graph is correct?

The relationship between v and t is A If Q = 1, then P = 2.
represented by the equation B The gradient of the graph is 1.
C P is directly proportional to Q.
D The equation of the graph is P = 1 + 3Q
1-20

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