1-0-understanding-physics.pdf

Physics Module Form 4

1.1 Recognise the concepts of physics in everyday objects and natural phenomena

1.2 Recognise physical quantity and unit

Chapter 1 – Introduction to physics

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

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P H Y S I C S

1. Tick () the statements that are related to physics. Blood circulation in our body is controlled by heart. A large truck moves faster than a car because it has a more powerful engine. We need water in our digestion system. 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.

UNDERSTANDING BASE AND DERIVED QUANTITIES 1. Identify Physical quantities, Magnitude, Units and Measuring instrument from the statements below. Write them into the table below (next page). 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.

Statement

Physical quantity

Magnitude

A B C D E F 1-1

Unit

Measuring instrument

Physics Module Form 4 Define base quantities and derived quantities are


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2. Identify base quantities and derived quantity from the equation below. (a) Volume = length x length x length 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 Pressure Time Length Area Weight Force Work Energy Velocity Mass

S.I UNIT Second Kelvin Joule m s-1

Current Temperature Volume Power

Newton kilogram m2 meter

Ampere Pascal Watt m3

3. Choose base quantities from the physical quantities given above and state their S.I units. No.

Base Quantity

1. 2. 3. 4. 5.

1-2

S.I Unit

Physics Module Form 4 List some derived quantities and their S.I units


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4. Write 5 derived quantities from physical quantities given in the box above (previous page) and state their S.I units. No.

Derived Quantity

S.I Unit

1. 2. 3. 4. 5. Express quantities using scientific notation

Express quantities using prefixes

5. Rewrite the values below in scientific notation (Standard notation) No.

Original value

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

Scientific notation

6. Arrange the prefixes given below in ascending order. Then, state their multiple / submultiple. PREFIXES Nano (n) mega (M) deci (d) hector (h)

No.

kilo (k) centi (c) deca (da) micro ()

Prefix

pico (p) giga (G) tera (T) milli (m)

Multiple / Sub-multiple

1. 2. 3. 4. 5. 6. Solving problem involving conversion of units

MULTIPLE / SUB-MULTIPLE 103 109 1 10 10-12 10-6 102 -9 10 10-3

No.

10-2 106 10-1 1012

Multiple / Sub-multiple

Prefix

7. 8. 9. 10. 11. 12.

1. Rewrite the values below using the suitable prefix. (i) (ii)

4.1 x 1012 m 1

= __________

(vii)

3.8 x 102 K 9

= __________

9.3 x 10 s

= __________

(viii) 1.7 x 10 W

= __________

(iii) 0.5 x 10-3 J

= __________

(ix)

4.1 x 103 C

= __________

= __________

(x)

9.5 x 10-6 A

= __________

(iv) (v) (vi)

11.2 x 10-2 N 6

5.9 x 10 V -9

6.6 x 10 m

= __________ = __________

1-3

(xi) (xii)

8.6 x 10

-12 -1

m

2.2 x 10 s

= __________ = __________



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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 unit? Physical quantity A B C D

Temperature Time Mass Length

5. Which of the following physical quantities is not a base quantity?

S.I unit

A B

Celcius minute Newton metre

base scalar

C D

C D

Temperature Electric current

6. A radio station airs its programmes by 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 B

Weight Time

A B C D

vector derived

1.023 x 102 1.023 x 105 1.023 x 106 1.023 x 108

7. Which of the following values is equal to 470 pF?

3. Which of the following shows the correct relationship between the base quantities for density?

A B C D

A

4.7 x 10-10 F 4.7 x 1011 F 4.7 x 10-7 F 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 B

D

0.09 0.86

C D

1.16 11.61

9. Which measurement is the longest? 4. Which of the following is not a base S.I unit? A B

Gram Kelvin

C D

A B C D

Ampere Meter 1-4

2.68 x 103 m 2.68 x 10-1 mm 2.68 x 103 cm 2.68 x 10-4 m



10. Which of the following conversion of unit is correct? A B C D

24 mm3 300 mm3 800 mm3 1 000 mm3

1. 3

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11. Which of the following frequencies is the same as 106.8 MHz?

= 2.4 x 10-6 m3 = 3.0 x 10-7 m3 = 8.0 x 10-2 m3 = 1.0 x 10-4 m3

A B C D E

1.068 x 10-4 Hz 1.068 x 10-1 Hz 1.068 x 102 Hz 1.068 x 106 Hz 1.068 x 108 Hz

UNDERSTANDING SCALAR AND VECTOR QUANTITIES

Define scalar and vector quantities.

1. Read the statements below to make a generalisation on scalar quantity and vector 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

(i)

Vector Quantity

Scalar quantity is physical quantity that has _______________________.

(ii) Vector quantity is physical quantity that has _______________________ and ________________________. Differentiate between distance and displacement.

2. Underline the correct physical quantity. (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.

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EXAMPLE: A

B

4m

A boy walks from A to C through B. (i)

3m

Distance of the boy

=4m+3m =7m

(ii) Displacement of the boy =

=5m

C

Check Yourself 2 1. Which of the following quantities is a vector quantity? A B

Energy Power

C D

3. Which quantity is a vector quantity? A B

Force Pressure

2. Diagram below shows the path travelled by a car from P to S. P

5 km

A B C D

Q

1 km

R

What is the displacement of the car? A B

5.0 km 6.8 km

C D

C D

Distance Displacement

4. Which of the following is group of vector quantities?

3 km

S

Area Length

8.2 km 9.0 km

1-6

Velocity, mass, displacement Speed, time, acceleration Force, velocity, displacement Area, temperature, momentum


1.4


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

Recognise appropriate instrument for physical quantities

M E A S U R E M E N T S

1. State the suitable measuring instrument for the physical quantities in the table below. MEASURING INSTRUMENT Metre rule Barometer Spring balance Hydrometer Ammeter Voltmeter Micrometer screw gauge

No.

Measure physical quantity using vernier calliper.

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Thermometer Measuring cylinder Stopwatch

Physical Quantity

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

Lever balance Bourdon gauge Vernier calliper

Measuring Instrument

2. Label the part of vernier calliper below. PART OF VERNIER CALLIPER Inner jaws Outer jaws

0

1

Main scale

2

1-7

3

Vernier scale

4

5

6



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3. Take the reading from a vernier calliper: EXAMPLE: (i) 0.70 cm 0

(i) Read the main scale. Main scale reading

(ii) Read the vernier scale. Vernier scale reading = 0.02 cm

2

1 0

(iii) Total up the readings. Actual reading

(ii) 0.02 cm 4. Read the vernier calliper below. (i)

3

= 0.70 cm

2

(ii)

4

= 0.72 cm

3

0

0 Main scale

= ....................

Main scale

= ....................

Vernier scale

= ....................

Vernier scale

= ....................

Actual reading

= ....................

Actual reading

= ....................

(ii)

8

(iv)

9

0

1

0

Measure physical quantity using micrometer screw gauge.

Main scale

= ....................

Main scale

= ....................

Vernier scale

= ....................

Vernier scale

= ....................

Actual reading

= ....................

Actual reading

= ....................

5. Label the part of micrometer screw gauge below. PART OF MICROMETER SCREW GAUGE Anvil Spindle Sleeve

1-8

Thimble

Ratchet



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6. Take the reading from a micrometer screw gauge. EXAMPLE: (i) Read the sleeve scale (main scale). Sleeve scale reading = 3.00 mm

(i) 3.00 mm 0

50 (ii) 0.44 mm

40

(ii) Read the thimble scale. Thimble scale reading = 0.44 mm (iii) Total up the readings. Actual reading = 3.44 mm

7. Read the micrometer screw gauge below: (i)

(ii) 0

0

30 20

20 10

Sleeve scale

= ....................

Sleeve scale

= ....................

Thimble scale

= ....................

Thimble scale

= ....................

Actual reading

= ....................

Actual reading

= ....................

(iii)

(iv) 0

0 20

60 50

10

Sleeve scale

= ....................

Sleeve scale

= ....................

Thimble scale

= ....................

Thimble scale

= ....................

Actual reading

= ....................

Actual reading

= ....................

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Physics Module Form 4 Explain sensitivity.


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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.

(i)

Instrument P

Instrument Q

Instrument R

10.1 cm

10.4 cm

9.6 cm

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 consistency (Precision)

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

Physics Module Form 4 Explain type of experimental error.


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11. In an experiment, the readings of measurement taken may have slightly difference due 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. .

2. A, B, C, and D show parts of four different balance scales. Which balance is the most sensitive?

A, B, C, and D shows the shooting marks on a target. Which marks can explain the concept of precision of a measurement? A

C

B

D

1-11

A

C

B

D



7. The diagrams show the scales on a pair of vernier callipers and a metre rule.

3. Diagram below shows the target board in a game. Target board

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Target

Which result is consistent but not accurate? A

C

B

Vernier calliper

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

D

A B C D

4. The diagram shows the scale of a micrometer screw gauge. 8.

Vernier callipers

Metre rule

Low sensitivity Low sensitivity High sensitivity High sensitivity

Low Sensitivity High sensitivity Low sensitivity High sensitivity

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

What is the reading of the micrometer? A B

7.02 mm 7.52 mm

C D

A B C D

7.03 mm 7.58 mm

9.

What is the reading of the vernier calliper? 2.16 cm 2.06 cm

C D

1 2.50 2.53 2.52 2.71

Reading/cm 2 3 2.50 2.50 2.53 2.53 2.53 2.54 2.73 2.74

4 2.50 2.53 2.53 2.74

Each student made four measurements. If the actual thickness of the board is 2.53 cm, which of the students A, B, C, and D made the measurements that are accurate but not consistent?

5. The diagram shows the scale of a vernier calliper.

A B

Metre rule

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

1.86 cm 1.76 cm

6. Atmospheric pressure can be measured by using A B C D

(a)

hydrometer Bourdon gauge and manometer Bourdon gauge and mercury barometer manometer and mercury barometer

(b)

What is the thickness of the metal sheet? A 0.46 cm C 0.38 cm B 0.42 cm D 0.32 cm 1-12



14. Which of the following statements is correct about zero error?

10. Four students, A, B, C, and D use a micrometer screw gauge, a metre rule, and a vernier calliper to measure the thickness of a board. Which student records the reading correctly? Micrometer screw gauge/mm A B C D

11.1 11.13 11.128 11.13

Metre rule/mm

A B

Vernier calliper/mm

C D 11 11.1 11.1 11

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11.13 11.128 11.13 11.1

Can be reduced by determining average reading. The magnitude of error increases when the value of the reading increases. Exist either in positive or negative. The magnitude of error increases if the range of scale is large.

15. Diagram below shows two types of ammeters, X and Y, that can be used to measure electric current.

11. The diagram shows the scale of a micrometer screw gauge.

What is the reading of the micrometer? A B

4.95 mm 4.55 mm

C D

4.50 mm 4.45 mm

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

(a) Which ammeter is more sensitive?

Use a higher sensitivity ammeter. Repeat the measurement and calculate the average reading. Take the reading using a magnifying glass. Use ammeter that has plane mirror below the pointer.

................................................................... (b) State one reason for your answer above. ................................................................... ...................................................................

13. What is the function of the plane mirror under the pointer in an ammeter? A B C D

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

To increase the consistency of the measurement. To increase the accuracy of the measurement. To avoid parallax error. To prevent zero error.

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(a) The external diameters of the cylinder at four different places are shown in the table below.

16. Figure below shows the scale of an ammeter.

External diameter/cm

Mirror

2.04

2.05

2.04

Relative deviation/%

2.06

(i) Why is the external measured four times?

0.37

diameter

............................................................. (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 taking the reading of the volume of oil?

(b) Name the part labelled X. ...................................................................

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

(c) What is the function of X?

(b) Give one reason for the answer above.

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

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

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

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

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19. A student is assigned to measure the thickness of a metal sheet. The student is provided with a vernier calliper.

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(i) What is the zero error of the vernier calliper? .............................................................

(a) The student uses the vernier calliper to measure the thickness of the metal sheet. Figure (i) shows the scale of the vernier calliper while the jaws are closed. Figure (ii) shows the scale of the vernier calliper when the metal sheet is put between the jaws.

(ii) Calculate the thickness of the metal sheet.

(i)

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

1.5

UNDERSTANDING SCIENTIFIC INVESTIGATION

Identify variables in a given situation

1.

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

No. 1. 2. 3. 4. 5.

Cause

: pushed harder

Manipulated variable

: Force

Effect

: moves faster

Responding variable

: Speed/Velocity/ Acceleration


Situation The temperature of smaller block rises faster when it is heated. The pendulum system with longer string takes longer time to stop. The loaded lorry is harder to stop than the empty lorry. The trolley that falls from the higher place moves faster. The spring becomes longer when it is pulled harder. 1-15

Responding variable

Physics Module Form 4 Making inference

2.


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Write inference from the given variables. EXAMPLE: Manipulated variable : Length

Responding variable: Time

Inference : The length affects the time taken.

Form hypothesis.

No.


Responding variable

1.

Force

Acceleration

2.

Mass

Temperature

3.

Force

Extension

4.

Mass

Time

5.

Force

Pressure

6.

Area

Pressure

7.

Temperature

Volume

3.

Inference

Write hypothesis from the given variables. EXAMPLE: Manipulated variable : Length

Responding variable: Time

Hypothesis : The longer the length, the longer the time taken. No.


Responding variable

1.

Force

Acceleration

2.

Mass

Temperature

3.

Force

Extension

4.

Mass

Time

5.

Force

Pressure

6.

Area

Pressure

7.

Temperature

Volume

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Hypothesis

Physics Module Form 4 Analyse the data.

4.


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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 Responding variable

: Acceleration

(iii) Manipulated variable : Force Responding variable

: Extension

1-17

(ii) Manipulated variable Responding variable

: Mass : Temperature

(iv)

: Mass : Time

Manipulated variable Responding variable


(v)

Interpret data to draw a conclusion.

6.



: Force

(vi)

Responding variable

: Pressure

Manipulated variable Responding variable

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: Area : Pressure

The conclusion of an experiment is made based on the line graph obtained. EXAMPLE: Pressure/Pa

Time/min

m-2 Mass/kg Conclusion:

Conclusion:

The time is directly proportional to the mass.

The pressure is inversely proportional to the area.

Temperature/C

Time/min Conclusion: The temperature is linearly increasing with the time.

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Interpret data to draw a conclusion.


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7. Write a conclusion based on the line graphs below: (i) Period2/s2

(ii) Temperature/C

kg-2 Length/cm Conclusion:

Conclusion:

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

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

(iii)

(iv)

Volume/m3

Extension/cm

Force/N

Pressure/kPa Conclusion:

Conclusion:

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

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

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Check Yourself 4 1.

Which of the following graphs obeys the equation F = kx, where k is a constant?

A

C

A

B

D

. C

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

B

2.

D

Which of the following variables are correct?

Table below shows the results of an experiment to investigate between load and extension when a spring is stretched. Load, F/N

100

150

200

250

300

Extension, x/cm

1.0

1.5

2.0

2.5

3.0

The original length of the spring is l0 = 15.0 cm. What is the manipulated variable? A B C D

Load, F Extension, x Original length of the spring, l0 Material used to make the spring


Responding variable

Constant variable

A Mass of the baby B Length of the spring C Diameter of the spring D Mass of the baby

Length of the spring Mass of the baby Length of the spring Diameter of the spring

Diameter of the spring Diameter of the spring Mass of the baby Length of the spring

5. The graph shows the relationship between physical quantities P and Q.

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

Which statements about the graph is correct? The relationship between v and represented by the equation

t

is

A B C D 1-20

If Q = 1, then P = 2. The gradient of the graph is 1. P is directly proportional to Q. The equation of the graph is P = 1 + 3Q

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