SlideShare uma empresa Scribd logo
1 de 50
Baixar para ler offline
PREPARED BY:
Mdm Heiana Nadia Hamzah
1. A force is a push or a
pull acting on an
object.
2. When we push or pull
on an object, we are
exerting a force on it.
Identify whether the activities below are
push or pull actions:
a) Pressing the plasticine
b) Stretching the plasticine
c) Climbing a tree
d) Ride on a bicycle
e) Walk on the ground
f) Chopping onion with a knife
push
push
push
pull
pull
push
plasticine
PUSH
PULL
A B C
State the effect of force on each of the following activities:
A : Press & stretch the lump of plasticine
B : Shifting a wooden block to the side of the table
C : Blow gently & hard at the ping-pong ball in the opposite direction
Changes the shape of the plasticine
Changes the position of the wooden block
Changes the speed & direction of movement of ping-pong ball.
Let‘s do Activity 7.1
ACTIVITY OBSERVATION
A
B
C
D
E
F
G
Force change the shape & size of the spring.
Force change the shape & size of the span.
Force move a stationary trolley.
Force increase the speed of a moving trolley.
Force slow down a moving trolley.
Force stop a moving slotted weight.
Force change the direction of the magnet.
3. Applying forces to an object can cause;
• A change of shape of an object
3. Applying forces to an object can
cause;
• Move a stationary object.
• Change its position or direction.
• Increase or decrease the speed of a
moving object.
• Slow down & stop a moving object.
a)GRAVITATIONAL FORCE
• It is the force that pulls object to the Earth’s surface
A stone that is
thrown upward
will falls down
because of
gravitational
force.
• The force of gravity acts
equally on all objects.
• In a vacuum, all objects fall
with the same velocity.
Figure 1: objects fall with the same
acceleration in a vacuum (left) but
with different accelerations through
air (right)
Air resistance.
Different parts of the Earth experience
different gravitational forces.
Equator
North pole
South pole
Explanation
•This is because the Earth
is oval.
•The force of gravity is
stronger at the poles &
weaker at the equator.
•Gravity is stronger when
you are closer to the
centre of the Earth.
b)FRICTIONAL FORCE
•A force that opposes the movement of one surface
over another.
•Produced when two surfaces touch one another.
c)ELECTROSTATIC FORCE
• It is the force of attraction
between unlike charges or the
force of repulsion between like
charges.
c) ELECTROSTATIC FORCE
• It is produced by charged objects, which
are non-conductors of electricity. This
may be a plastic, glass & rubber.
• When a plastic ruler is rubbed with a dry,
woolen cloth, the ruler becomes
charged. It can attract small pieces of
paper that are not charged.
d)MAGNETIC FORCE
• It is the force of attraction or repulsion between magnets or
magnetic material.
• Like poles of magnets repel each other.
• Different poles of magnet attract each other.
e) ELECTROMAGNET
• An electromagnet is a type
of magnet in which the
magnetic field is produced
by the flow of electric
current.
• An electromagnet is a
temporary magnet.
• The magnetic field
disappears when the
current is turned off.
solenoid
1. The unit of force is the newton (N)
2. A spring balance is used to measure the
magnitude.
3. If a spring is 5 cm long and a load
stretches it to 8 cm long, then the
extension of the spring is…
8 – 5 = 3 cm
• The extension of a spring is directly proportional to the
weight of a load.
• The extension of the spring increases when the load on
the spring increases.
Try this out...!
QUESTION
Figure shows the extension of a spring by 2 cm when a
load of 4 N was suspended on it.
Calculate the increase in length when a load of 6 N is
suspended on it.
SOLUTION
4 N extend 2 cm
6 N extend ? cm
6/ 4 x 2 = 3 cm
Extension of the spring = 3 cm
QUESTION 2
A spring without any load has the length of 10 cm. This
spring stretches to 35 cm if a load of 25 N is attached to
it. What is the extension of the same spring if a load of
10 N is attached to it.
ANSWER
10 cm
A cup that is
placed on a
table does not
move. WHY?
The cup does not move because
of the friction between the
table & the cup.
The magnitude of the frictional force that acts
between two surfaces depends on the…
a) Nature of the surfaces
• If the surfaces are rough, the
frictional force will be greater.
• If there is oil or grease between
the surfaces, the frictional force
will be smaller.
Rough surface will generate more friction compare to the
smooth surface.
A
B
b. Weight of the moving object
The greater the weight, the greater the frictional
force.
A
B
Frictional force does not depend on
the area of contact surface.
EXPERIMENT 7.1:
HOW DIFFERENT TYPES OF SURFACES AFFECT
FRICTIONAL FORCE
TYPES OF SURFACES MAGNITUDE OF
FRICTIONAL FORCE (N)
Table
Sand paper
Glass rods
Beans
CONCLUSION:
______________________________________________The rougher the surface, the greater the frictional force.
What are the
advantages of
frictional force?
ADVANTAGES OF FRICTIONAL FORCE
1. Enable us to carry out daily activities
such as walking, running, climbing,
dancing etc.
ADVANTAGES OF FRICTIONAL FORCE
2. Braking system making moving
vehicles slow down or stop.
ADVANTAGES OF FRICTIONAL FORCE
3. Enable us to hold things.
4. Enables us to move without slipping.
ADVANTAGES OF FRICTIONAL FORCE
5. Enable things to lean on.
What are the
disadvantages of
frictional force?
DISADVANTAGES OF FRICTIONAL FORCE
1. More energy is needed to move a
vehicle or object
2. Causes the surface in contact to wear
out.
3. Produces unnecessary heat –
Car engines becomes hotter because of friction.
The wooden block is just about to move when the
spring balance shows 4 N.
Which statements below is correct regarding the
magnitude and direction of friction.
A. The magnitude of friction is twice that shows on the
spring balance and acts in the same direction as the
pulling force.
B. The magnitude of friction is 4N and it acts in the
opposite direction to movement.
C. The magnitude of friction 2N and it acts in the
opposite direction to movement
pulled
Methods of reducing friction
1. Rollers or ball bearings reduce
friction.
2. Lubricants such as oils & grease are
applied to moving parts to reduce
friction.
Methods of reducing friction
3. A space shuttle is streamlined to reduce
friction & provide very little resistance to
a flow of air.
4. Hydrofoil boat The layer of air
between the hull of a hydrofoil &
the water allows the hydrofoil to
move at high speed.
Methods of reducing friction
5. HOVERCRAFT 
Vehicle that moves above
water or land by gliding on a
cushion of air it creates by
blowing downward.
Methods of reducing friction
6. MAGLEV TRAIN
This train use the basic principle of magnet. As the train
floats on the track, there is no contact with the ground,
so less friction is produced.
1. Work is the product of the force acting on an object & the
distance moved by the object in the direction of the force.
2. S.I. unit for work is newton metre (Nm) or joule (J).
3. Work is also a measure of the amount of energy used.
WORK
Work done (J) = Force (N) x Distance moved in the
direction of the force (m)
FORMULA
WORK
wall
Is work done in the above situation?
nO work is done in above situation.
Work is done when a force moves an object
over a distance.
Try this out...!
QUESTION 1
Jamie uses 200 J of energy to lift a 10 kg box to a certain
height. What is the height?
Solution
[Assume 1 kg = 10 N]
200 J = 100 N x d
d = 200/ 100
d = 2 m
1. Power is the rate of work done
2. The S.I unit for power is joule per second ( Js⁻ ˡ ) or
watt (W).
3. Power is a measure of how fast work is done.
POWER
Power (W) = Work done (J)
Time taken (s)
FORMULA
Try this out...!
QUESTION 2
A boy weighs 55 kg carries
a box of 2kg when
climbing a stairs of vertical
height 5 metres. Calculate
the work done by him.
ANSWER
2850 Nm/ 2850 J
Try this out...!
QUESTION 3
A girl weighs 45 kg carries
books of 3kg. She climbs a
stairs in 20 seconds.
Calculate the power
generated by her.
ANSWER
72 Watt
Try this out...!
QUESTION 4
A student climbs up a 6m high staircase with a 3.5 kg
parcel in 40 seconds. If the power used by the
student is 87 W, what is the mass of the student?
ANSWER 54.5 kg
Try this out...!
QUESTION 5
A soldier weighing 750 N carries a knapsack & a rifle
weighing 100 N and 50 N respectively. He is ordered to go on
a 10 km march. How much power does the soldier have if he
completes the march in 5 hours?
Solution
[Assume 1 km = 1000 m]
Work done (J) = (750 + 100 + 50) N x (10 km x 1000) m
= 9 000 000 Nm
Power (W) = 9 000 000 Nm / (5 hours x 60 x 60) s
= 500 W
1. A man carrying a sack of rice walks for 40 m in 20
seconds. He weighs 50 kg and the sack of rice weighs
10 kg. How much power does he produce?
2. A pupil weighing 60 kg climbs 15 steps up a staircase
in 40 seconds. Each step of the stairs is 20 cm high.
How much power is produced as he climbs the stairs?
3. A car weighing 500 kg is being towed through a
distance of 0.4 km. How much power in kW is needed
to tow a car in 10 seconds?
QUESTION 1
A spring of 7 cm is stretched to 10 cm when a 10 N load is
placed on it. A load X is placed on it & the spring stretched
to 13 cm. Find the weight of load X?
ANSWER
Weight of load X = 20 N

Mais conteúdo relacionado

Mais procurados

Laporan Amali Biologi: Sel Haiwan dan Sel Tumbuhan
Laporan Amali Biologi: Sel Haiwan dan Sel TumbuhanLaporan Amali Biologi: Sel Haiwan dan Sel Tumbuhan
Laporan Amali Biologi: Sel Haiwan dan Sel TumbuhanAtifah Ruzana Abd Wahab
 
Kerja lapangan geografi tingkatan 3
Kerja lapangan geografi tingkatan 3Kerja lapangan geografi tingkatan 3
Kerja lapangan geografi tingkatan 3Ummu Umar
 
24.tekanan dalam cecair
24.tekanan dalam cecair24.tekanan dalam cecair
24.tekanan dalam cecairAtiqah Azmi
 
Penyelesaian Masalah secara inventif (Bab 1)
Penyelesaian Masalah secara inventif (Bab 1)Penyelesaian Masalah secara inventif (Bab 1)
Penyelesaian Masalah secara inventif (Bab 1)Athirah Syafiqah Baharom
 
Organisasi sel amoeba (sarah)
Organisasi sel amoeba (sarah)Organisasi sel amoeba (sarah)
Organisasi sel amoeba (sarah)Nurul Azuwin
 
GEOGRAFI TINGKATAN 2 BAB 6
GEOGRAFI TINGKATAN 2 BAB 6 GEOGRAFI TINGKATAN 2 BAB 6
GEOGRAFI TINGKATAN 2 BAB 6 najwanabila
 
3.0 daya dan tekanan
3.0 daya dan tekanan3.0 daya dan tekanan
3.0 daya dan tekananMrHan Physics
 
Sains Tahun 6: Unit 4 Interaksi Antara Hidupan
Sains Tahun 6: Unit 4 Interaksi Antara HidupanSains Tahun 6: Unit 4 Interaksi Antara Hidupan
Sains Tahun 6: Unit 4 Interaksi Antara HidupanTutor
 
Kesan pergerakan kerak bumi ting 1
Kesan pergerakan kerak bumi ting 1Kesan pergerakan kerak bumi ting 1
Kesan pergerakan kerak bumi ting 1sabanti
 
Pengekstrakan mineral
Pengekstrakan mineralPengekstrakan mineral
Pengekstrakan mineralIzzat Najmi
 
Spm 2007 paper 2 + skima
Spm 2007 paper 2 + skimaSpm 2007 paper 2 + skima
Spm 2007 paper 2 + skimaNurul Fadhilah
 
F4 Experiments
F4 ExperimentsF4 Experiments
F4 Experimentsmarjerin
 
Bab 6 Sumber Tenaga
Bab 6 Sumber TenagaBab 6 Sumber Tenaga
Bab 6 Sumber TenagaSafwan Yusuf
 
Teknik menjawab Fizik SPM 2... more detail
Teknik menjawab Fizik SPM 2... more detailTeknik menjawab Fizik SPM 2... more detail
Teknik menjawab Fizik SPM 2... more detailCikgu Pejal
 
132441402 chapter-3-movement-of-substances-across-the-plasma-membrane
132441402 chapter-3-movement-of-substances-across-the-plasma-membrane132441402 chapter-3-movement-of-substances-across-the-plasma-membrane
132441402 chapter-3-movement-of-substances-across-the-plasma-membraneLim Yee Yern
 

Mais procurados (20)

Laporan Amali Biologi: Sel Haiwan dan Sel Tumbuhan
Laporan Amali Biologi: Sel Haiwan dan Sel TumbuhanLaporan Amali Biologi: Sel Haiwan dan Sel Tumbuhan
Laporan Amali Biologi: Sel Haiwan dan Sel Tumbuhan
 
Kerja lapangan geografi tingkatan 3
Kerja lapangan geografi tingkatan 3Kerja lapangan geografi tingkatan 3
Kerja lapangan geografi tingkatan 3
 
Bab 1 momentum
Bab 1 momentumBab 1 momentum
Bab 1 momentum
 
7.3 Daya geseran
7.3 Daya geseran7.3 Daya geseran
7.3 Daya geseran
 
24.tekanan dalam cecair
24.tekanan dalam cecair24.tekanan dalam cecair
24.tekanan dalam cecair
 
Penyelesaian Masalah secara inventif (Bab 1)
Penyelesaian Masalah secara inventif (Bab 1)Penyelesaian Masalah secara inventif (Bab 1)
Penyelesaian Masalah secara inventif (Bab 1)
 
Organisasi sel amoeba (sarah)
Organisasi sel amoeba (sarah)Organisasi sel amoeba (sarah)
Organisasi sel amoeba (sarah)
 
Inersia
Inersia Inersia
Inersia
 
GEOGRAFI TINGKATAN 2 BAB 6
GEOGRAFI TINGKATAN 2 BAB 6 GEOGRAFI TINGKATAN 2 BAB 6
GEOGRAFI TINGKATAN 2 BAB 6
 
3.0 daya dan tekanan
3.0 daya dan tekanan3.0 daya dan tekanan
3.0 daya dan tekanan
 
Sains Tahun 6: Unit 4 Interaksi Antara Hidupan
Sains Tahun 6: Unit 4 Interaksi Antara HidupanSains Tahun 6: Unit 4 Interaksi Antara Hidupan
Sains Tahun 6: Unit 4 Interaksi Antara Hidupan
 
Kesan pergerakan kerak bumi ting 1
Kesan pergerakan kerak bumi ting 1Kesan pergerakan kerak bumi ting 1
Kesan pergerakan kerak bumi ting 1
 
Pengekstrakan mineral
Pengekstrakan mineralPengekstrakan mineral
Pengekstrakan mineral
 
Hujan asid
Hujan asid Hujan asid
Hujan asid
 
Guidelines On Writing English Essays SPM
Guidelines On Writing English Essays SPMGuidelines On Writing English Essays SPM
Guidelines On Writing English Essays SPM
 
Spm 2007 paper 2 + skima
Spm 2007 paper 2 + skimaSpm 2007 paper 2 + skima
Spm 2007 paper 2 + skima
 
F4 Experiments
F4 ExperimentsF4 Experiments
F4 Experiments
 
Bab 6 Sumber Tenaga
Bab 6 Sumber TenagaBab 6 Sumber Tenaga
Bab 6 Sumber Tenaga
 
Teknik menjawab Fizik SPM 2... more detail
Teknik menjawab Fizik SPM 2... more detailTeknik menjawab Fizik SPM 2... more detail
Teknik menjawab Fizik SPM 2... more detail
 
132441402 chapter-3-movement-of-substances-across-the-plasma-membrane
132441402 chapter-3-movement-of-substances-across-the-plasma-membrane132441402 chapter-3-movement-of-substances-across-the-plasma-membrane
132441402 chapter-3-movement-of-substances-across-the-plasma-membrane
 

Destaque

Chapter 7 dynamics
Chapter 7 dynamicsChapter 7 dynamics
Chapter 7 dynamicsIzudin Hasan
 
Chapter 9 stability
Chapter 9 stabilityChapter 9 stability
Chapter 9 stabilityIzudin Hasan
 
Chapter 8 support and movement
Chapter 8 support and movementChapter 8 support and movement
Chapter 8 support and movementIzudin Hasan
 
Chapter 6 air pressure
Chapter 6 air pressureChapter 6 air pressure
Chapter 6 air pressureIzudin Hasan
 
51145703 form-2-science-chapter-7 (1)
51145703 form-2-science-chapter-7 (1)51145703 form-2-science-chapter-7 (1)
51145703 form-2-science-chapter-7 (1)ranesan
 
Chapter 3 biodiversity
Chapter 3 biodiversityChapter 3 biodiversity
Chapter 3 biodiversityIzudin Hasan
 
Chapter 10 simple machine
Chapter 10 simple machineChapter 10 simple machine
Chapter 10 simple machineIzudin Hasan
 
Express Notes Science Form 2
Express Notes Science Form 2Express Notes Science Form 2
Express Notes Science Form 2science-resources
 
Water & solution SCIENCE FORM 2
Water & solution SCIENCE FORM 2Water & solution SCIENCE FORM 2
Water & solution SCIENCE FORM 2Nur Hidayah Taib
 
Support and movement[1]
Support and movement[1]Support and movement[1]
Support and movement[1]Anas Mariam
 
Science form 2 power point
Science form 2 power pointScience form 2 power point
Science form 2 power pointsuerieya81
 
Chapter 5 water and solution
Chapter 5 water and solutionChapter 5 water and solution
Chapter 5 water and solutionIzudin Hasan
 
Science Form 2:Chapter 1
Science Form 2:Chapter 1Science Form 2:Chapter 1
Science Form 2:Chapter 1rizfarizan
 
Chapter 4 interdependence among living organisms and the envirronment
Chapter 4 interdependence among living organisms and the envirronmentChapter 4 interdependence among living organisms and the envirronment
Chapter 4 interdependence among living organisms and the envirronmentIzudin Hasan
 
Chapter 2 nutrition
Chapter 2 nutritionChapter 2 nutrition
Chapter 2 nutritionIzudin Hasan
 
Form 1 Chapter 2- Cell as a Unit of Life
Form 1 Chapter 2- Cell as a Unit of LifeForm 1 Chapter 2- Cell as a Unit of Life
Form 1 Chapter 2- Cell as a Unit of LifeHui Ying
 
Science form 2
Science form 2Science form 2
Science form 2Ain Azmi
 

Destaque (20)

Chapter 7 dynamics
Chapter 7 dynamicsChapter 7 dynamics
Chapter 7 dynamics
 
Chapter 9 stability
Chapter 9 stabilityChapter 9 stability
Chapter 9 stability
 
Chapter 8 support and movement
Chapter 8 support and movementChapter 8 support and movement
Chapter 8 support and movement
 
Chapter 6 air pressure
Chapter 6 air pressureChapter 6 air pressure
Chapter 6 air pressure
 
51145703 form-2-science-chapter-7 (1)
51145703 form-2-science-chapter-7 (1)51145703 form-2-science-chapter-7 (1)
51145703 form-2-science-chapter-7 (1)
 
Chapter 3 biodiversity
Chapter 3 biodiversityChapter 3 biodiversity
Chapter 3 biodiversity
 
7.3 friction
7.3 friction7.3 friction
7.3 friction
 
Chapter 10 simple machine
Chapter 10 simple machineChapter 10 simple machine
Chapter 10 simple machine
 
Express Notes Science Form 2
Express Notes Science Form 2Express Notes Science Form 2
Express Notes Science Form 2
 
Water & solution SCIENCE FORM 2
Water & solution SCIENCE FORM 2Water & solution SCIENCE FORM 2
Water & solution SCIENCE FORM 2
 
Support and movement[1]
Support and movement[1]Support and movement[1]
Support and movement[1]
 
Science form 2 power point
Science form 2 power pointScience form 2 power point
Science form 2 power point
 
Air Pressure!
Air Pressure!Air Pressure!
Air Pressure!
 
Chapter 5 water and solution
Chapter 5 water and solutionChapter 5 water and solution
Chapter 5 water and solution
 
Science Form 2:Chapter 1
Science Form 2:Chapter 1Science Form 2:Chapter 1
Science Form 2:Chapter 1
 
Chapter 4 interdependence among living organisms and the envirronment
Chapter 4 interdependence among living organisms and the envirronmentChapter 4 interdependence among living organisms and the envirronment
Chapter 4 interdependence among living organisms and the envirronment
 
Chapter 1 form 2
Chapter 1 form 2Chapter 1 form 2
Chapter 1 form 2
 
Chapter 2 nutrition
Chapter 2 nutritionChapter 2 nutrition
Chapter 2 nutrition
 
Form 1 Chapter 2- Cell as a Unit of Life
Form 1 Chapter 2- Cell as a Unit of LifeForm 1 Chapter 2- Cell as a Unit of Life
Form 1 Chapter 2- Cell as a Unit of Life
 
Science form 2
Science form 2Science form 2
Science form 2
 

Semelhante a Form 2 science chapter 7

Unit 6, Lesson 1 - Force
Unit 6, Lesson 1 - ForceUnit 6, Lesson 1 - Force
Unit 6, Lesson 1 - Forcejudan1970
 
Apphysicsbexamreview 090423004425-phpapp02
Apphysicsbexamreview 090423004425-phpapp02Apphysicsbexamreview 090423004425-phpapp02
Apphysicsbexamreview 090423004425-phpapp02Cleophas Rwemera
 
Apphysicsbexamreview 090425125639-phpapp01
Apphysicsbexamreview 090425125639-phpapp01Apphysicsbexamreview 090425125639-phpapp01
Apphysicsbexamreview 090425125639-phpapp01Cleophas Rwemera
 
Discussion Energy and Circular Motion Exercises.docx
Discussion Energy and Circular Motion Exercises.docxDiscussion Energy and Circular Motion Exercises.docx
Discussion Energy and Circular Motion Exercises.docxstirlingvwriters
 
1-4 Force.pptx
1-4 Force.pptx1-4 Force.pptx
1-4 Force.pptxChenKahPin
 
Force & pressure class 8
Force & pressure class 8Force & pressure class 8
Force & pressure class 8Preeti Khosla
 
Force_and_Work.pptx
Force_and_Work.pptxForce_and_Work.pptx
Force_and_Work.pptxFrancis1593
 
AP Physics B Exam Review
AP Physics B Exam ReviewAP Physics B Exam Review
AP Physics B Exam ReviewMrreynon
 
AP Physics B Exam Review
AP Physics B Exam ReviewAP Physics B Exam Review
AP Physics B Exam ReviewMrreynon
 
Forces
ForcesForces
Forcesmeenng
 
7E's Science Lesson plan
7E's Science Lesson plan7E's Science Lesson plan
7E's Science Lesson planDrMuttuVemula
 
7E's SCIENCE LESSON PLAN
7E's SCIENCE LESSON PLAN7E's SCIENCE LESSON PLAN
7E's SCIENCE LESSON PLANDrMuttuVemula
 
1a force motion 0
1a force  motion 01a force  motion 0
1a force motion 0millerdoe
 

Semelhante a Form 2 science chapter 7 (20)

Unit 6, Lesson 1 - Force
Unit 6, Lesson 1 - ForceUnit 6, Lesson 1 - Force
Unit 6, Lesson 1 - Force
 
Apphysicsbexamreview 090423004425-phpapp02
Apphysicsbexamreview 090423004425-phpapp02Apphysicsbexamreview 090423004425-phpapp02
Apphysicsbexamreview 090423004425-phpapp02
 
Apphysicsbexamreview 090425125639-phpapp01
Apphysicsbexamreview 090425125639-phpapp01Apphysicsbexamreview 090425125639-phpapp01
Apphysicsbexamreview 090425125639-phpapp01
 
Discussion Energy and Circular Motion Exercises.docx
Discussion Energy and Circular Motion Exercises.docxDiscussion Energy and Circular Motion Exercises.docx
Discussion Energy and Circular Motion Exercises.docx
 
TYPES OF FORSE
TYPES OF FORSETYPES OF FORSE
TYPES OF FORSE
 
Forces
ForcesForces
Forces
 
1-4 Force.pptx
1-4 Force.pptx1-4 Force.pptx
1-4 Force.pptx
 
Work.pptx
Work.pptxWork.pptx
Work.pptx
 
Force & pressure class 8
Force & pressure class 8Force & pressure class 8
Force & pressure class 8
 
Force_and_Work.pptx
Force_and_Work.pptxForce_and_Work.pptx
Force_and_Work.pptx
 
AP Physics B Exam Review
AP Physics B Exam ReviewAP Physics B Exam Review
AP Physics B Exam Review
 
AP Physics B Exam Review
AP Physics B Exam ReviewAP Physics B Exam Review
AP Physics B Exam Review
 
Ch 7 Momentum
Ch 7 MomentumCh 7 Momentum
Ch 7 Momentum
 
Forces
ForcesForces
Forces
 
7E's Science Lesson plan
7E's Science Lesson plan7E's Science Lesson plan
7E's Science Lesson plan
 
7E's SCIENCE LESSON PLAN
7E's SCIENCE LESSON PLAN7E's SCIENCE LESSON PLAN
7E's SCIENCE LESSON PLAN
 
Lecture 9
Lecture 9Lecture 9
Lecture 9
 
1a force motion 0
1a force  motion 01a force  motion 0
1a force motion 0
 
FORCE AND FRICTION
FORCE AND FRICTIONFORCE AND FRICTION
FORCE AND FRICTION
 
Force and motion
Force and motion Force and motion
Force and motion
 

Último

The basics of sentences session 10pptx.pptx
The basics of sentences session 10pptx.pptxThe basics of sentences session 10pptx.pptx
The basics of sentences session 10pptx.pptxheathfieldcps1
 
CAULIFLOWER BREEDING 1 Parmar pptx
CAULIFLOWER BREEDING 1 Parmar pptxCAULIFLOWER BREEDING 1 Parmar pptx
CAULIFLOWER BREEDING 1 Parmar pptxSaurabhParmar42
 
Practical Research 1 Lesson 9 Scope and delimitation.pptx
Practical Research 1 Lesson 9 Scope and delimitation.pptxPractical Research 1 Lesson 9 Scope and delimitation.pptx
Practical Research 1 Lesson 9 Scope and delimitation.pptxKatherine Villaluna
 
5 charts on South Africa as a source country for international student recrui...
5 charts on South Africa as a source country for international student recrui...5 charts on South Africa as a source country for international student recrui...
5 charts on South Africa as a source country for international student recrui...CaraSkikne1
 
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptx
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptxPractical Research 1: Lesson 8 Writing the Thesis Statement.pptx
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptxKatherine Villaluna
 
How to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 SalesHow to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 SalesCeline George
 
3.21.24 The Origins of Black Power.pptx
3.21.24  The Origins of Black Power.pptx3.21.24  The Origins of Black Power.pptx
3.21.24 The Origins of Black Power.pptxmary850239
 
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...Nguyen Thanh Tu Collection
 
What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?TechSoup
 
Education and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxEducation and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxraviapr7
 
CapTechU Doctoral Presentation -March 2024 slides.pptx
CapTechU Doctoral Presentation -March 2024 slides.pptxCapTechU Doctoral Presentation -March 2024 slides.pptx
CapTechU Doctoral Presentation -March 2024 slides.pptxCapitolTechU
 
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptxPISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptxEduSkills OECD
 
How to Add Existing Field in One2Many Tree View in Odoo 17
How to Add Existing Field in One2Many Tree View in Odoo 17How to Add Existing Field in One2Many Tree View in Odoo 17
How to Add Existing Field in One2Many Tree View in Odoo 17Celine George
 
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdf
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdfP4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdf
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdfYu Kanazawa / Osaka University
 
Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.raviapr7
 
Prescribed medication order and communication skills.pptx
Prescribed medication order and communication skills.pptxPrescribed medication order and communication skills.pptx
Prescribed medication order and communication skills.pptxraviapr7
 
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdfMaximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdfTechSoup
 
Patient Counselling. Definition of patient counseling; steps involved in pati...
Patient Counselling. Definition of patient counseling; steps involved in pati...Patient Counselling. Definition of patient counseling; steps involved in pati...
Patient Counselling. Definition of patient counseling; steps involved in pati...raviapr7
 

Último (20)

The basics of sentences session 10pptx.pptx
The basics of sentences session 10pptx.pptxThe basics of sentences session 10pptx.pptx
The basics of sentences session 10pptx.pptx
 
Finals of Kant get Marx 2.0 : a general politics quiz
Finals of Kant get Marx 2.0 : a general politics quizFinals of Kant get Marx 2.0 : a general politics quiz
Finals of Kant get Marx 2.0 : a general politics quiz
 
Prelims of Kant get Marx 2.0: a general politics quiz
Prelims of Kant get Marx 2.0: a general politics quizPrelims of Kant get Marx 2.0: a general politics quiz
Prelims of Kant get Marx 2.0: a general politics quiz
 
CAULIFLOWER BREEDING 1 Parmar pptx
CAULIFLOWER BREEDING 1 Parmar pptxCAULIFLOWER BREEDING 1 Parmar pptx
CAULIFLOWER BREEDING 1 Parmar pptx
 
Practical Research 1 Lesson 9 Scope and delimitation.pptx
Practical Research 1 Lesson 9 Scope and delimitation.pptxPractical Research 1 Lesson 9 Scope and delimitation.pptx
Practical Research 1 Lesson 9 Scope and delimitation.pptx
 
5 charts on South Africa as a source country for international student recrui...
5 charts on South Africa as a source country for international student recrui...5 charts on South Africa as a source country for international student recrui...
5 charts on South Africa as a source country for international student recrui...
 
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptx
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptxPractical Research 1: Lesson 8 Writing the Thesis Statement.pptx
Practical Research 1: Lesson 8 Writing the Thesis Statement.pptx
 
How to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 SalesHow to Manage Cross-Selling in Odoo 17 Sales
How to Manage Cross-Selling in Odoo 17 Sales
 
3.21.24 The Origins of Black Power.pptx
3.21.24  The Origins of Black Power.pptx3.21.24  The Origins of Black Power.pptx
3.21.24 The Origins of Black Power.pptx
 
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...
CHUYÊN ĐỀ DẠY THÊM TIẾNG ANH LỚP 11 - GLOBAL SUCCESS - NĂM HỌC 2023-2024 - HK...
 
What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?What is the Future of QuickBooks DeskTop?
What is the Future of QuickBooks DeskTop?
 
Education and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptxEducation and training program in the hospital APR.pptx
Education and training program in the hospital APR.pptx
 
CapTechU Doctoral Presentation -March 2024 slides.pptx
CapTechU Doctoral Presentation -March 2024 slides.pptxCapTechU Doctoral Presentation -March 2024 slides.pptx
CapTechU Doctoral Presentation -March 2024 slides.pptx
 
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptxPISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
PISA-VET launch_El Iza Mohamedou_19 March 2024.pptx
 
How to Add Existing Field in One2Many Tree View in Odoo 17
How to Add Existing Field in One2Many Tree View in Odoo 17How to Add Existing Field in One2Many Tree View in Odoo 17
How to Add Existing Field in One2Many Tree View in Odoo 17
 
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdf
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdfP4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdf
P4C x ELT = P4ELT: Its Theoretical Background (Kanazawa, 2024 March).pdf
 
Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.Drug Information Services- DIC and Sources.
Drug Information Services- DIC and Sources.
 
Prescribed medication order and communication skills.pptx
Prescribed medication order and communication skills.pptxPrescribed medication order and communication skills.pptx
Prescribed medication order and communication skills.pptx
 
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdfMaximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
Maximizing Impact_ Nonprofit Website Planning, Budgeting, and Design.pdf
 
Patient Counselling. Definition of patient counseling; steps involved in pati...
Patient Counselling. Definition of patient counseling; steps involved in pati...Patient Counselling. Definition of patient counseling; steps involved in pati...
Patient Counselling. Definition of patient counseling; steps involved in pati...
 

Form 2 science chapter 7

  • 1. PREPARED BY: Mdm Heiana Nadia Hamzah
  • 2. 1. A force is a push or a pull acting on an object. 2. When we push or pull on an object, we are exerting a force on it.
  • 3. Identify whether the activities below are push or pull actions: a) Pressing the plasticine b) Stretching the plasticine c) Climbing a tree d) Ride on a bicycle e) Walk on the ground f) Chopping onion with a knife push push push pull pull push
  • 5. A B C State the effect of force on each of the following activities: A : Press & stretch the lump of plasticine B : Shifting a wooden block to the side of the table C : Blow gently & hard at the ping-pong ball in the opposite direction Changes the shape of the plasticine Changes the position of the wooden block Changes the speed & direction of movement of ping-pong ball.
  • 6. Let‘s do Activity 7.1 ACTIVITY OBSERVATION A B C D E F G Force change the shape & size of the spring. Force change the shape & size of the span. Force move a stationary trolley. Force increase the speed of a moving trolley. Force slow down a moving trolley. Force stop a moving slotted weight. Force change the direction of the magnet.
  • 7. 3. Applying forces to an object can cause; • A change of shape of an object
  • 8. 3. Applying forces to an object can cause; • Move a stationary object. • Change its position or direction. • Increase or decrease the speed of a moving object. • Slow down & stop a moving object.
  • 9. a)GRAVITATIONAL FORCE • It is the force that pulls object to the Earth’s surface A stone that is thrown upward will falls down because of gravitational force.
  • 10. • The force of gravity acts equally on all objects. • In a vacuum, all objects fall with the same velocity. Figure 1: objects fall with the same acceleration in a vacuum (left) but with different accelerations through air (right) Air resistance.
  • 11. Different parts of the Earth experience different gravitational forces. Equator North pole South pole Explanation •This is because the Earth is oval. •The force of gravity is stronger at the poles & weaker at the equator. •Gravity is stronger when you are closer to the centre of the Earth.
  • 12. b)FRICTIONAL FORCE •A force that opposes the movement of one surface over another. •Produced when two surfaces touch one another.
  • 13. c)ELECTROSTATIC FORCE • It is the force of attraction between unlike charges or the force of repulsion between like charges.
  • 14. c) ELECTROSTATIC FORCE • It is produced by charged objects, which are non-conductors of electricity. This may be a plastic, glass & rubber. • When a plastic ruler is rubbed with a dry, woolen cloth, the ruler becomes charged. It can attract small pieces of paper that are not charged.
  • 15. d)MAGNETIC FORCE • It is the force of attraction or repulsion between magnets or magnetic material. • Like poles of magnets repel each other. • Different poles of magnet attract each other.
  • 16. e) ELECTROMAGNET • An electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current. • An electromagnet is a temporary magnet. • The magnetic field disappears when the current is turned off. solenoid
  • 17. 1. The unit of force is the newton (N) 2. A spring balance is used to measure the magnitude. 3. If a spring is 5 cm long and a load stretches it to 8 cm long, then the extension of the spring is… 8 – 5 = 3 cm
  • 18. • The extension of a spring is directly proportional to the weight of a load. • The extension of the spring increases when the load on the spring increases.
  • 19. Try this out...! QUESTION Figure shows the extension of a spring by 2 cm when a load of 4 N was suspended on it. Calculate the increase in length when a load of 6 N is suspended on it.
  • 20. SOLUTION 4 N extend 2 cm 6 N extend ? cm 6/ 4 x 2 = 3 cm Extension of the spring = 3 cm
  • 21. QUESTION 2 A spring without any load has the length of 10 cm. This spring stretches to 35 cm if a load of 25 N is attached to it. What is the extension of the same spring if a load of 10 N is attached to it. ANSWER 10 cm
  • 22. A cup that is placed on a table does not move. WHY? The cup does not move because of the friction between the table & the cup.
  • 23. The magnitude of the frictional force that acts between two surfaces depends on the… a) Nature of the surfaces • If the surfaces are rough, the frictional force will be greater. • If there is oil or grease between the surfaces, the frictional force will be smaller.
  • 24. Rough surface will generate more friction compare to the smooth surface. A B
  • 25. b. Weight of the moving object The greater the weight, the greater the frictional force. A B
  • 26. Frictional force does not depend on the area of contact surface.
  • 27. EXPERIMENT 7.1: HOW DIFFERENT TYPES OF SURFACES AFFECT FRICTIONAL FORCE TYPES OF SURFACES MAGNITUDE OF FRICTIONAL FORCE (N) Table Sand paper Glass rods Beans CONCLUSION: ______________________________________________The rougher the surface, the greater the frictional force.
  • 28. What are the advantages of frictional force?
  • 29. ADVANTAGES OF FRICTIONAL FORCE 1. Enable us to carry out daily activities such as walking, running, climbing, dancing etc.
  • 30. ADVANTAGES OF FRICTIONAL FORCE 2. Braking system making moving vehicles slow down or stop.
  • 31. ADVANTAGES OF FRICTIONAL FORCE 3. Enable us to hold things. 4. Enables us to move without slipping.
  • 32. ADVANTAGES OF FRICTIONAL FORCE 5. Enable things to lean on.
  • 33. What are the disadvantages of frictional force?
  • 34. DISADVANTAGES OF FRICTIONAL FORCE 1. More energy is needed to move a vehicle or object 2. Causes the surface in contact to wear out. 3. Produces unnecessary heat – Car engines becomes hotter because of friction.
  • 35. The wooden block is just about to move when the spring balance shows 4 N. Which statements below is correct regarding the magnitude and direction of friction. A. The magnitude of friction is twice that shows on the spring balance and acts in the same direction as the pulling force. B. The magnitude of friction is 4N and it acts in the opposite direction to movement. C. The magnitude of friction 2N and it acts in the opposite direction to movement pulled
  • 36. Methods of reducing friction 1. Rollers or ball bearings reduce friction. 2. Lubricants such as oils & grease are applied to moving parts to reduce friction.
  • 37. Methods of reducing friction 3. A space shuttle is streamlined to reduce friction & provide very little resistance to a flow of air. 4. Hydrofoil boat The layer of air between the hull of a hydrofoil & the water allows the hydrofoil to move at high speed.
  • 38. Methods of reducing friction 5. HOVERCRAFT  Vehicle that moves above water or land by gliding on a cushion of air it creates by blowing downward.
  • 39. Methods of reducing friction 6. MAGLEV TRAIN This train use the basic principle of magnet. As the train floats on the track, there is no contact with the ground, so less friction is produced.
  • 40. 1. Work is the product of the force acting on an object & the distance moved by the object in the direction of the force. 2. S.I. unit for work is newton metre (Nm) or joule (J). 3. Work is also a measure of the amount of energy used. WORK Work done (J) = Force (N) x Distance moved in the direction of the force (m) FORMULA
  • 41. WORK wall Is work done in the above situation? nO work is done in above situation. Work is done when a force moves an object over a distance.
  • 42. Try this out...! QUESTION 1 Jamie uses 200 J of energy to lift a 10 kg box to a certain height. What is the height? Solution [Assume 1 kg = 10 N] 200 J = 100 N x d d = 200/ 100 d = 2 m
  • 43. 1. Power is the rate of work done 2. The S.I unit for power is joule per second ( Js⁻ ˡ ) or watt (W). 3. Power is a measure of how fast work is done. POWER Power (W) = Work done (J) Time taken (s) FORMULA
  • 44. Try this out...! QUESTION 2 A boy weighs 55 kg carries a box of 2kg when climbing a stairs of vertical height 5 metres. Calculate the work done by him. ANSWER 2850 Nm/ 2850 J
  • 45. Try this out...! QUESTION 3 A girl weighs 45 kg carries books of 3kg. She climbs a stairs in 20 seconds. Calculate the power generated by her. ANSWER 72 Watt
  • 46. Try this out...! QUESTION 4 A student climbs up a 6m high staircase with a 3.5 kg parcel in 40 seconds. If the power used by the student is 87 W, what is the mass of the student? ANSWER 54.5 kg
  • 47. Try this out...! QUESTION 5 A soldier weighing 750 N carries a knapsack & a rifle weighing 100 N and 50 N respectively. He is ordered to go on a 10 km march. How much power does the soldier have if he completes the march in 5 hours?
  • 48. Solution [Assume 1 km = 1000 m] Work done (J) = (750 + 100 + 50) N x (10 km x 1000) m = 9 000 000 Nm Power (W) = 9 000 000 Nm / (5 hours x 60 x 60) s = 500 W
  • 49. 1. A man carrying a sack of rice walks for 40 m in 20 seconds. He weighs 50 kg and the sack of rice weighs 10 kg. How much power does he produce? 2. A pupil weighing 60 kg climbs 15 steps up a staircase in 40 seconds. Each step of the stairs is 20 cm high. How much power is produced as he climbs the stairs? 3. A car weighing 500 kg is being towed through a distance of 0.4 km. How much power in kW is needed to tow a car in 10 seconds?
  • 50. QUESTION 1 A spring of 7 cm is stretched to 10 cm when a 10 N load is placed on it. A load X is placed on it & the spring stretched to 13 cm. Find the weight of load X? ANSWER Weight of load X = 20 N

Notas do Editor

  1. 1 newton = 100 g1 kg= 10 newtons