Chapter 2 Forces and Motion
-
Upload
sazlin-a-ghani -
Category
Documents
-
view
279 -
download
17
description
Transcript of Chapter 2 Forces and Motion
Chapter 2 Force And MotionChapter 2 Force And Motion
ITeach – Physics Form 4
2.1 Analysing Linear Motion
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Linear Motion
Linear motion is the motion of an object whose path is a straight line
Running a 100 m race
An apple falling from tree
A moving bullet
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Gerakan Linear
Gerakan linear ialah gerakan ssesuatu objek dalam lintasan lurus atau dalam garis lurus.
Berlari sejauh 100 m
Epal jatuh daripada pokok
Peluru yang sedang bergerak
An athlete ran a 400 m race in a time of 80.0 seconds.
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Speed Velocity
A scalar quantity A vector quantity
Speed And
Velocity
Example
Distance ran = 400 m Displacement = zero (0) m Speed = distance / time Velocity = displacement / time
= 400 / 80.0 = 0 / 80.0= 5 m s-1 = 0 m s-1
Rate of change of distance Rate of change of displacement
Speed = distance travelled / time Velocity = displacement / time
Seorang atlet berlari dalam lumba lari 400 m dalam masa 80.0 saat.
ITeach – Fizizk Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Laju Halaju
Suatu kuantiti skalar Suatu kuantiti vektor
Laju dan
Halaju
Contoh
Jarak berlari = 400 m Sesaran = Sifar (0) m Laju = jarak / masa Halaju = sesaran / masa
= 400 / 80.0 = 0 / 80.0= 5 m s-1 = 0 m s-1
Kadar perubahan jarak Kadar perubahan sesaran
Laju = jarak dilalui / masa Halaju = sesaran / masa
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Acceleration And Deceleration
A vector quantity When an object accelerates, its velocity changes.
For an object in linear motionObject accelerating, velocityObject decelerating, velocity
Acceleration, a =
final velocity, v – initial velocity, u
time, t
u is the velocity of an object at the start of its motion
v is the velocity of an object at the end of its motion
a is the rate of change of velocity
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Pecutan dan Nyahpecutan
Suatu kuantiti vektor Apabila suatu objek memecut, halajunya berubah.
Objek bergerak dalam garisan linearObjek memecut , halajuObjek nyahpecut, halaju
Pecutan , a =
Halaju akhir, v – Halaju awal, u
Masa, t
u Halaju objek ketika ia mula bergerak
v Halaju objek di akhir gerakan
a Kadar perubahan halaju
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Numerical Example Acceleration And Deceleration
A car starts form rest and accelerates uniformly achieving a velocity of 50 m s-1 in a time of 10 seconds.
Initial velocity u = 0 m s-1 (car at rest / stationary) Final velocity v = 50 m s-1
Time t = 10 s
Acceleration, a = v – u t
a = 50 – 0 10
a = 5 m s-2
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Contoh BerangkaPecutan dan Nyahpecutan
Sebuah kereta bergerak daripada keadaan rehat dengan pecutan seragam sehingga ia mencapai halaju 50 m s-1 dalam masa 10 saat.
Halaju awal u = 0 m s-1 (kereta dalam keadaan rehat / pegun) Halaju akhir v = 50 m s-1
Masa t = 10 s
Pecutan , a = v – u t
a = 50 – 0 10
a = 5 m s-2
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Ticker Timer
Used together with a trolley to study linear motion in the laboratory.
Powered by a 12 V AC power supply of frequency 50 Hertz.
The metal strip (vibrator) vibrates 50 times in 1 second when connected to power.
The vibrating metal strip punches dots on the carbonized ticker tape.
trolleyrunwaytimer
coil
magnet
ticker tape
AC power
vibrating bar
carbon paper disc
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Jangka Masa Detik
Digunakan bersama troli untuk mengkaji gerakan linear di dalam makmal.
Satu bekalan kuasa 12 V AC digunakan dengan frekuensi 50 Hertz.
Jalur bergetar bergetar 50 kali setiap 1 saat apabila ia bersambung dengan bekalan kuasa.
Jalur bergetar menebuk titik pada pita detik berkarbon.
trolilandasanJangka
masa
gelung
magnet
Pita jangka masa detik
Kuasa AC
Jalur bergetar
Pita detik berkarbon
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
The Ticker Tape
• Shows a comprehensive record of the motion of the trolley that pulls the ticker tape through the ticker timer.
• The vibration metal strip makes 51 dots on the ticker tape per second.
• The time interval between two successive dots is called a tick.
dots
1 tick
• 50 ticks are made on the ticker tape in 1 second.
• Therefore the duration of 1 tick is 1/50 = 0.02 seconds.
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Pita Jangka Masa Detik
• Menunjukkan rekod gerakan troli.
• Jalur berdetik membuat 51 titik pada pita jangka masa detik setiap 1 saat.
• Sela masa antara dua titik dipanggil satu detik.
titik
1 detik
• Terdapat 50 titik pada pita jangka masa detik dalam masa 1 saat.
• Tempoh masa untuk setiap 1 titik ialah 1/50 = 0.02 saat.
The motion of an object can be deduced by studying the ticks formed on the ticker tape.
Analysis Of The Ticker Tape
Uniform but small
Uniform but big
Increasing in size
Decreasing in size
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Type Of Motion
Gap between successive dots
low but uniform velocity.
high but uniform velocity.
velocity increases, object accelerating.
velocity decreases, object decelerating.
Type of motion Ticker tape
Jenis gerakan objek boleh ditakikkan dari jarak antara titik pada pita jangka masa detik.
Menganalisis Pita Jangka Masa Detik
Seragam dan jarak antara titik kecil
Seragam dan jarak antara titik besar
Jarak antara titik bertambah
Jarak antara titik berkurangan
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Jenis Gerakan
Sela antara titik
Halaju perlahan dan seragam
Halaju tinggi dan seragam
Halaju bertambah, objek memecut
Halaju berkurangan, objek nyahpecut
Jenis gerakanPita jangka masa detik
Analysis Of The Ticker Tape
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Determining Average Velocity
The speed of the object pulling the ticker tape through the ticker timer can be determined as such
Average velocity = length of n ticks time for n ticks
Example8 cm
Number of ticks = 3length of 3 ticks = 8 cmtime for 3 ticks = (3)(0.02) = 0.06 s
Average velocity = (length of 3 ticks)/(time for 3 ticks) = 8 cm / 0.06 s = 133.33 cm s-1
Menganalisis Pita Jangka Masa Detik
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Menentukan Purata Halaju
Purata halaju objek dapat ditentukan melalui:
Purata halaju = Panjang n titik
Masa bagi n titik
Contoh8 cm
Bilangan titik = 3Panjang 3 titik = 8 cmMasa bagi 3 titik = (3)(0.02) = 0.06 s
Purata halaju = (penjang 3 titik)/(masa bagi 3 titik) = 8 cm / 0.06 s = 133.33 cm s-1
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Analysis Of The Ticker Tape
Determining Acceleration
Initial velocity, u = 0.4cm / 0.02s = 20 cm/s
Final velocity , v = 2.4cm / 0.02s = 120 cm/s
Time = ( total number of ticks –1 ) x ( 0.02 )
= ( 11 – 1 ) x ( 0.02 )
= 10 0.02
= 0.2s
Acceleration, a = v – u t
a = 120 – 20 0.2
a = 100 / 0.2 = 500 cm s-2
0.4 cm 2.4 cm1
tick
2 tic
ks3
ticks
4 tic
ks
5 tic
ks
6 tic
ks
7 tic
ks
8 tic
ks
9 tic
ks
10 ti
cks
11 ti
cks
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Menganalisis Pita Jangka Masa Detik
Menentukan Pecutan
Halaju awal , u = 0.4cm / 0.02s = 20 cm/s
Halaju akhir , v = 2.4cm / 0.02s = 120 cm/s
Masa = ( Jumlah bilangan titik –1 ) x ( 0.02 )
= ( 11 – 1 ) x ( 0.02 )
= 10 0.02
= 0.2s
Pecutan , a = v – u t
a = 120 – 20 0.2
a = 100 / 0.2 = 500 cm s-2
0.4 cm 2.4 cm1
titik
2 tit
ik3
titik
4 tit
ik
5 tit
ik
6 tit
ik
7 tit
ik
8 tit
ik
9 tit
ik
10 ti
tik11
titik
Characteristics Of Ticker Tape Chart - Uniform Velocity
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
The distance between successive dots are equally spaced.
All the ticker tapes are of the same length.
Time
Length (cm)
0
1
234
56
7
Ciri-ciri Carta Pita Jangka Masa Detik – Halaju Sekata
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Jarak antara titik-titik adalah sama.
Keratan pita sama panjang
Masa
Panjang (cm)
0
1
234
56
7
Characteristics Of Ticker Tape Chart - Uniform Acceleration
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Distance between successive dots increases uniformly.
Length of ticker tapes increases uniformly.
2.0
3.0
4.0
5.0
6.0
7.0Length / cm
Time
Ciri-ciri Carta Pita Jangka Masa Detik – Pecutan Seragam
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Jarak antara titik bertambah secara seragam
Panjang keratan pita bertambah secara seragam
2.0
3.0
4.0
5.0
6.0
7.0Panjang / cm
Masa
Characteristics Of Ticker Tape Chart - Uniform Deceleration
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Distance between successive dots decreases uniformly.
Length of ticker tapes decreases uniformly.
2.0
3.0
4.0
5.0
6.0
7.0Length / cm
Time
Ciri-ciri Carta Pita Jangka Masa Detik – Nyahpecutan Seragam
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Jarak antara titik berkurangan secara seragam
Panjang pita berkurangan secara seragam
2.0
3.0
4.0
5.0
6.0
7.0Panjang / cm
Masa
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Equations Of Linear Motion With Constant Acceleration
The three equations of linear motion with constant acceleration
v = u + at 2asuv 22 2at 21 +ut = s
where
u initial velocity =
v final velocity=
a acceleration=
t time=
s displacement=
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Persamaan Gerakan Linear dengan Pecutan Seragam
Tiga persamaan gerakan linear dengan pecutan seragam
v = u + at 2asuv 22 2at 21 +ut = s
dimana
u Halaju awal=
v Halaju akhir=
a Pecutan=
t Masa=
s Sesaran=
Using the equation, v = u + at
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Equations Of Linear Motion With Constant Acceleration
Example 1
A car starts from rest, accelerates with a uniform acceleration of 3 ms -2. What will the velocity of the car after it had travelled for 10 seconds ?
initial velocity u = 0 ms-1 (since the car is at rest /stationary ) acceleration a = 3 ms-2 time taken t = 10 s
Solution :
final velocity v = ?
= 0 + (3)(10)
= 30 m s-1
The car will be moving at a velocity of 30 ms-1 after 10 seconds.
Menggunakan persamaan, v = u + at
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Persamaan Gerakan Linear dengan Pecutan Seragam
Contoh 1
Sebuah kereta bergerak daripada keadaan rehat memecut dengan pecutan seragam 3 ms-2. Berapakah pecutan kereta itu selepas bergerak selama 10 saat?
Halaju awal u = 0 ms-1 (kereta dalam keadaan rehat sebelum bergerak) Pecutan a = 3 ms-2 Masa t = 10 s
Penyelesaian :
Halaju akhir v = ?
= 0 + (3)(10)
= 30 m s-1
Kereta itu bergerak pada halaju 30 ms-1 selepas 10 saat.
ITeach – Physics Form 4
Analysing Linear MotionChapter 2 Force And Motion
Equations Of Linear Motion With Constant Acceleration
Example 2
A rocket being launched accelerates vertically upwards with a uniform acceleration of 50 ms-2.
How far is the rocket from the surface of the earth after 2 minutes of the launch?
initial velocity u = 0 ms-1 (rocket was stationary before launched)
acceleration a = 50 ms-2 time t = 2 60 = 120 s
Solution :
height from earth’s surface s = ?
2at 21 +ut = s 2(50)(120)
21 + (0)(120) =
= 360000 m= 360 km
Using the equation,
ITeach – Fizik Tingkatan 4
Menganalisis Gerakan LinearBab 2 Daya dan Gerakan
Persamaan Gerakan Linear dengan Pecutan Seragam
Contoh 2
Sebuah roket yang baru dilancarkan memecut secara menegak ke atas dengan pecutan seragam 50 ms-2.
Berapa jauhkah roket itu daripada permukaan Bumi selepas 2 minit dilancarkan?
Halaju awal u = 0 ms-1 (roket dalam keadaan rehat sebelum dilancarkan) Pecutan a = 50 ms-2
Masa t = 2 60 = 120 s
Penyelesaian :
Ketinggian daripada permukaan Bumi s = ?
2at 21 +ut = s 2(50)(120)
21 + (0)(120) =
= 360000 m= 360 km
Menggunakan persamaan,
Chapter 2 Force And MotionChapter 2 Force And Motion
ITeach – Physics Form 4
2.2 2.2 Analysing Motion GraphsAnalysing Motion Graphs
Displacement – time graphs
ITeach – Physics Form 4
Analysing Motion FraphsChapter 2 Forces and Motion
Can determine the displacement of an object at any time.
Can determine the time taken for an object to cover certain displacement.
Displacement / m
Time/s
75
60
45
30
15
10 20 30 40 50
At time t = 40 s, the displacement of object is 60 m.
The time taken for the object at the displacement 15 m is 10 s.
Example
To show the displacement of an object changes with time.
Graf sesaran - masa
ITeach – Fizik Tingkatan 4
Menganalisis Graf GerakanBab 2 Daya dan Gerakan
Boleh menentukan sesaran objek pada masa tertentu.
Boleh menentukan masa yang diambil oleh suatu objek untuk setiap sesaran.
Sesaran / m
Masa/s
75
60
45
30
15
10 20 30 40 50
Pada masa t = 40 s, sesaran objek ialah 60 m.
Masa yang diambil objek pada sesaran 15 m ialah 10 s.
Contoh
Menunjukkan sesaran objek berubah dengan masa.
Determining Velocity - Displacement-Time Graph
ITeach – Physics Form 4
Analysing Motion GraphsChapter 2 Force And Motion
Displacement/m
Time/s
75
60
45
30
15
10 20 30 40 50
Example
velocity = gradient of displacement-time graph
velocity = gradient of displacement-time graph
velocity = 60 – 15
40 – 10
= 45 30
= 1.5 ms-1
Menentukan Halaju – Graf Sesaran - Mas
ITeach – Fizik Tingkatan 4
Menganalisis Graf GerakanBab 2 Daya dan Gerakan
Sesaran/m
Masa/s
75
60
45
30
15
10 20 30 40 50
Contoh
Halaju = Kecerunan graf sesaran - masa
Halaju = kecerunan graf sesaran - masa
Halaju = 60 – 15
40 – 10
= 45 30
= 1.5 ms-1
Velocity-Time Graph
ITeach – Physics Form 4
Analysing Motion GraphsChapter 2 Force And Motion
shows how the velocity of a moving object changes with time.
Velocity, v/ms-1
Time, t/s
25
20
15
10
5
1 2 3 4 50
30
Example
When time, t = 4 s, the velocity of the object is 20 ms-1
It takes 3 seconds for the object to achieve a velocity of 15 ms-1
Graf Halaju - Masa
ITeach – Fizik Tingkatan 4
Menganalisis Graf GerakanBab 2 Daya dan Gerakan
Menunjukkan bagaimana halaju bagi objek bergerak berubah dengan masa.
Halaju, v/ms-1
Masa, t/s
25
20
15
10
5
1 2 3 4 50
30
Contoh
Pada masa, t = 4 s, halaju objek ialah 20 ms-1
Objek itu mengambil masa 3 saat untuk mencapai halaju 15 ms-1
Determining Acceleration - Velocity-Time Graph
ITeach – Physics Form 4
Analysing Motion GraphsChapter 2 Force And Motion
Acceleration = gradient of the velocity-time graph
Acceleration = gradient of the velocity-time graph
Velocity, v/ms-1
Time, t/s
25
20
15
10
5
1 2 3 4 50
30
Example
acceleration = 20 – 0 4 – 0
= 204
= 5 ms-2
Menentukan Pecutan – Graf Halaju - Masa
ITeach – Fizik Tingkatan 4
Menganalisis Graf GerakanBab 2 Daya dan Gerakan
Pecutan = kecerunan graf halaju - masa
Pecutan = kecerunan pada graf halaju - masa
Halaju, v/ms-1
Masa, t/s
25
20
15
10
5
1 2 3 4 50
30
Contoh
Pecutan = 20 – 0 4 – 0
= 204
= 5 ms-2
Determining Displacement - Velocity-Time Graph
ITeach – Physics Form 4
Analysing Motion GraphsChapter 2 Force And Motion
The displacement of the object = area under the velocity-time graph
10
4 9
Velocity, v
Time, t/s
Displacement of the object from time, t = 4s to time, t = 9s, = area under the graph
= area of shaded region
(10)(5) 21 =
= 25 m
Example
Menentukan Sesaran – Graf Halaju - Masa
ITeach – Fizik Tingkatan 4
Menganalisis Graf GerakanBab 2 Daya dan Gerakan
Sesaran objek = Luas di bawah graf halaju - masa
10
4 9
Halaju, v
Masa, t/s
Sesaran objek daripada masa, t = 4s hingga masa, t = 9s, = luas di bawah graf
= luas kawasan berlorek
(10)(5) 21 =
= 25 m
Contoh
ITeach – Physics Form 4
Analysing Motion GraphsChapter 2 Force And Motion
Summary Of Motion Graphs
Gradient Velocity Acceleration
Area under the graph -------- Displacement
Displacement-time graph
Velocity-time graph
ITeach – Fizik Tingkatan 4
Menganalisis Graf GerakanBab 2 Daya dan Gerakan
Ringkasan Graf Gerakan
Kecerunan Halaju Pecutan
Luas di bawah graf -------- Sesaran
Graf sesaran - masa Graf halaju - masa
Chapter 2 Force And MotionChapter 2 Force And Motion
ITeach – Physics Form 4
2.3 2.3 Understanding InertiaUnderstanding Inertia
Observation
Explanation
Understanding Inertia
ITeach – Physics From 4
Inertia – Object At Rest
Inertia is a property of an object that causes it to resist any change to its state of motion.
Example
Chapter 2 Force And Motion
When the cardboard is flicked, the coin will drop into the glass.
An object that is at rest, will resist any effort to move it.
Coin at rest The coin’s inertia will resist any effort to move it.
Cardboard flicked The coin stays in its original position.
No cardboard
support
Gravity causes the coin to fall into the glass.
Pemerhatian
Penerangan
Memahami Inersia
ITeach – Fizik Tingkatan 4
Inersia – Objek dalam keadaan rehat
Inersia ialah kecenderungan objek menentang sebarang usaha untuk menggerakkannya daripada keadaan rehat.
Contoh
Bab 2 Daya dan Gerakan
Apabila kadbod ditarik, duit syiling akan jatuh ke dalam gelas.
Objek dalam keadaan rehat akan menentang sebarang usaha untuk menggerakkannya.
Syiling dalam keadaan rehat
Inersia syiling akan menentang sebarang usaha untuk menggerakkannya.
Kadbod ditarik Syiling kekal pada kedudukan asalnya.
Tanpa sokongan kadbod
Graviti menyebabkan syiling jatuh ke dalam gelas.
Observation
Explanation
Understanding Inertia
ITeach – Physics From 4
Inertia –Object In Motion
Example
Chapter 2 Force And Motion
When the bus was moving
The passengers on the bus were also initially moving forward.
When the bus was stopped
The inertia of the passengers caused them to continue to move forward.
An object in motion will continue to move in a straight line unless acted upon by an external force.
When the bus stopped abruptly, the passengers were thrown forward.
Pemerhatian
Penerangan
Memahami Inersia
ITeach – Fizik Tingkatan 4
Inersia – Objek sedang bergerak
Contoh
Bab 2 Daya dan Gerakan
Apabila bas sedang
bergerak
Penumpang juga bergerak ke hadapan.
Apabila bas berhenti
Inersia menyebabkan penumpang terus bergerak ke hadapan.
Objek yang sedang bergerak akan terus bergerak dalam satu garis lurus kecuali ditindakkan oleh daya luar.
Penumpang akan terhumban ke hadapan apabila bas yang sedang bergerak berhenti secara tiba-tiba.
Chapter 2 Forces and Motion
Understanding Inertia
ITeach – Physics From 4
Inertia And Mass – Object At Rest
The inertia of an object depends on its mass.
An stationary object with a higher inertia is harder to be moved than an object with a lower inertia.
inertiaMass
Smaller mass
Empty trolley Trolley full of things
Hence it is easier to push an empty trolley.
Therefore lower inertia. Bigger mass
Hence it is harder to push a trolley full of things.
Therefore higher inertia.
Bab 2 Daya dan Gerakan
Memahami Inersia
ITeach – Fizik Tingkatan 4
Inersia dan Jisim – Objek Dalam Keadaan Rehat
Inersia suatu objek bergantung kepada jisimnya.
Objek pegun dengan inersia yang tinggi adalah susah untuk digerakkan berbanding objek yang mempunyai inersia yang rendah.
InersiaJisim
Jisim kecil
Troli kosong Troli yang dipenuhi barang
Lebih mudah untuk menggerakkan troli kosong.
Inersia yang kurang Jisim yang besar
Lebih susah untuk menggerakkan troli yang dipenuhi barang.
Inersia yang lebih tinggi
Hence, it is more difficult to stop a moving aero-plane.
Chapter 2 Forces and Motion
Understanding Inertia
ITeach – Physics From 4
A moving object with a bigger mass is more difficult to stop than an object with a smaller mass.
Inertia And Mass – Object In Motion
Example
Smaller mass
Hence it is easier to stop a moving bicycle.
Therefore lower inertia.
Bicycle Aero-plane
Bigger mass Therefore higher inertia.
Lebih susah untuk menghentikan kapal terbang.
Bab 2 Daya dan Gerakan
Memahami Inersia
ITeach – Fizik Tingkatan 4
Objek yang sedang bergerak dengan jisim yang besar adalah susah untuk diberhentikan berbanding objek yang mempunyai jisim yang kecil.
Inersia dan Jisim – Objek Sedang Bergerak
Contoh
Jisim kecil
Lebih mudah untuk menghentikan basikal.
Inersia rendah
Basikal Kapal terbang
Jisim yang lebih besar Inersia tinggi
Explanation
The hammer head and the handle moves when it is on its downward motion.
When handle touches the floor, the handle stops suddenly but the hammer head will continue to move downwards due to its inertia.
Hence the hammer head tightens.
Chapter 2 Forces and Motion
Understanding Inertia
ITeach – Physics From 4
The head of a hammer can be tightened by hitting the handle on the floor.
Positive Effects Of Inertia – Tightening A Hammer Head
Penerangan
Kepala penukul dan pemegangnya sedang bergerak apabila penukul dalam gerakan ke bawah.
Apabila pemegang menyentuh lantai, pemegang akan berhenti bergerak tetapi kepala penukul akan terus bergerak ke bawah disebabkan oleh inersia.
Maka, kepala penukul diketatkan.
Bab 2 Daya dan Gerakan
Memahami Inersia
ITeach – Fizik Tingkatan 4
Kepala penukul boleh diketatkan dengan menghentak bahagian pemegangnya pada lantai.
Kesan Positif Inersia – Mengetatkan Kepala Penukul
Explanation
When the umbrella is being spun, the droplets on the umbrella is in a state of motion.
When the umbrella is stopped suddenly, the water droplets continues to move forward due its inertia and dislodge themselves form the umbrella.
Chapter 2 Forces and Motion
Understanding Inertia
ITeach – Physics From 4
Droplets of water dislodges themselves form a spinning umbrella when the umbrella is stopped abruptly.
Positive Effects Of Inertia – Drying An Umbrella
Penerangan
Titisan hujan pada payung dalam keadaan bergerak semasa payung berpusing.
Apabila payung berhenti berpusing secara tiba-tiba, titisan hujan akan terus bergerak ke hadapan disebabkan oleh inerisa dan titisan hujan keluar daripada payung.
Bab 2 Daya dan Gerakan
Memahami Inersia
ITeach – Fizik Tingkatan 4
Titisan air hujan keluar dan jatuh daripada payung apabila payung yang sedang berpusing diberhentikan serta merta.
Kesan Positif Inersia – Mengeringkan Payung
Chapter 2 Forces and Motion
Understanding Inertia
ITeach – Physics From 4
Reducing The Negative Effects Of Inertia
When a car stops suddenly, the inertia of the passenger will cause him to move forward.
Seat Belt
The seat belt holds the passenger back, preventing the passenger form hitting the dashboard or the windscreen of the car.
Bab 2 Daya dan Gerakan
Memahami Inersia
ITeach – Fizik Tingkatan 4
Mengurangkan Kesan Negatif Inersia
Apabila sebuah kereta berhenti dengan tiba-tiba, penumpang akan bergerak ke hadapan disebabkan oleh inersia.
Tali Pinggang
Tali pinggang mengelakkan penumpang terhumban ke hadapan.
Chapter 2 Forces and Motion
Understanding Inertia
ITeach – Physics From 4
Air Bag
The airbag is either mounted under the dashboard of in the steering wheel.
Reducing The Negative Effects Of Inertia – Air Bag
The air bag will inflate automatically in the event of an accident.
The airbag prevents the car passengers from colliding with the dashboard or the steering.
Bab 2 Daya dan Gerakan
Memahami Inersia
ITeach – Fizik Tingkatan 4
Beg Udara
Beg udara diletakkan dibawah papan pemuka atau didalam stereng kereta.
Mengurangkan Kesan Negatif Inersia – Beg Udara
Beg udara akan mengembang secara automatik ketika kemalangan berlaku.
Beg udara menghalang penumpang daripada terhentak pada papan pemuka dan stereng kereta.
Chapter 2 Force And MotionChapter 2 Force And Motion
2.1 Arah Mata Angin
ITeach – Physics Form 4
2.4 Analysing Momentum
Chapter 2 Forces and Motion
Analysing Momentum
Definition Of Momentum
Momentum is defined as the product of the mass of an object and its velocity.
ITeach – Physics From 4
momentum = mass velocity = mv
Momentum is a vector quantity.
Momentum = mass velocity
= (2 kg)(4 ms-1)
= 8 kg ms-1
Momentum = mass velocity
= (4 kg)(- 2 ms-1)
= - 8 kg ms-1
4 ms-1
2 kg
2 ms-1
4 kg
Bab 2 Daya dan Gerakan
Menganalisis Momentum
Definisi Momentum
Momentum ditakrifkan sebagai hasil darab jisim dengan halaju.
ITeach – Fizik Tingkatan 4
Momentum = Jisim Halaju = mv
Momentum ialah kuantiti vektor.
Momentum = jisim halaju
= (2 kg)(4 ms-1)
= 8 kg ms-1
Momentum = jisim halaju
= (4 kg)(- 2 ms-1)
= - 8 kg ms-1
4 ms-1
2 kg
2 ms-1
4 kg
Chapter 2 Forces and Motion
Analysing Momentum
ITeach – Physics From 4
Principle Of Conservation Of Momentum
The total momentum of colliding objects before collision The total momentum after collision.=
The total momentum of colliding objects before collision is the same as the total momentum after collision.
= m1u1 + m2u2 m1v2 + m2v2
Bab 2 Daya dan Gerakan
Menganalisis Momentum
ITeach – Fizik Tingkatan 4
Prinsip Keabadian Momentum
Jumlah momentum sebelum pelanggaran
Jumlah momentum selepas pelanggaran=
Jumlah momentum objek-objek sebelum pelanggaran adalah sama dengan jumlah momentum selepas pelanggaran jika tiada
daya bertindak ke atas objek-objek yang berlanggar.
= m1u1 + m2u2 m1v2 + m2v2
Chapter 2 Forces and Motion
Analysing Momentum
ITeach – Physics From 4
Momentum – Example
An object, P, of mass 4 kg moving with a velocity of 5 ms-1 collides with an object, Q, of mass 2 kg moving with a velocity of 1 ms-1 in the opposite direction.
If after the collision, object P moving with a velocity of 3 ms-1 in the same direction, determine the velocity of object Q after collision.
Solution
total momentum before collision = total momentum after collision mpup + mQuQ = mpvp + mQvQ
(4)(5) + (2)(-1) = (4)(3) + (2)(vQ)
20 – 2 = 12 + 2mQ
18 = 12 + 2mQ 2mQ = 6
mQ = 3 ms-1
Bab 2 Daya dan Gerakan
Menganalisis Momentum
ITeach – Fizik Tingkatan 4
Momentum – Contoh
Suatu objek, P, dengan jisim 4 kg sedang bergerak dengan halaju 5 ms -1 berlanggar dengan objek, Q, yang mempunyai jisim 2 kg dan bergerak dengan halaju1 ms-1 pada arah bertentangan.
Jika selepas pelanggaran, objek P bergerak dengan halaju 3 ms-1 pada arah yang sama, hitungkan halaju objek Q selepas pelanggaran.
Penyelesaian Jumlah momentum sebelum
pelanggaran = Jumlah momentum selepas
pelanggaran mpup + mQuQ = mpvp + mQvQ
(4)(5) + (2)(-1) = (4)(3) + (2)(vQ)
20 – 2 = 12 + 2mQ
18 = 12 + 2mQ 2mQ = 6
mQ = 3 ms-1
Before collision After collision
Characteristics
Objects moves separately after collision.
Total momentum is conserved.
Total kinetic energy is conserved.
Total energy is conserved.
Chapter 2 Forces and Motion
Analysing Momentum
ITeach – Physics From 4
Elastic Collision
Sebelum pelanggaran Selepas pelanggaran
Ciri-ciri
Objek bergerak berasingan selepas pelanggaran.
Jumlah momentum diabadikan.
Jumlah tenaga kinetik diabadikan.
Jumlah tenaga diabadikan.
Bab 2 Daya dan Gerakan
Menganalisis Momentum
ITeach – Fizik Tingkatan 4
Pelanggaran Kenyal
Characteristics
Objects stick to each other and move with a common velocity after collision.
Total momentum is conserved.
Total kinetic energy after collision is less than total kinetic energy before collision.
Total energy is conserved.
Chapter 2 Forces and Motion
Analysing Momentum
ITeach – Physics From 4
Before collision After collision
Inelastic Collision
Ciri-ciri
Objek bergerak bersama dengan halaju yang sama selepas pelanggaran.
Jumlah momentum diabadikan.
Jumlah tenaga kinetik selepas pelanggaran kurang daripada jumlah tenaga kinetik sebelum pelanggaran.
Jumlah tenaga diabadikan.
Bab 2 Daya dan Gerakan
Menganalisis Momentum
ITeach – Fizik Tingkatan 4
Sebelum pelanggaran Selepas pelanggaran
Pelanggaran Tak Kenyal
Applications Of Momentum
Chapter 2 Forces and Motion
Analysing Momentum
ITeach – Physics From 4
Tennis
Soccer
The space shuttle lifting off
A boy jumps forward, boat moves backwards
Kegunaan Momentum
Bab 2 Daya dan Gerakan
Menganalisis Momentum
ITeach – Fizik Tingkatan 4
Tenis
Bola sepak
Roket bergerak ke atas
Seorang budak lompat dari sebuah bot ke hadapan,
bot bergerak ke belakang
Chapter 2 Forces And Chapter 2 Forces And MotionMotion
2.1 Arah Mata Angin
ITeach – Physics Form 4
2.5 Understanding The Effect Of Force
ITeach – Physics Form 4
Understanding The Effect Of ForceChapter 2 Forces And Motion
Force is a physical quantity that when acted on an object will cause the object to experience a change in
Effect Of Force
• Shape
• Size
• Speed
• Direction of motion of an object
ITeach – Fizik Tingkatan 4
Memahami Kesan DayaBab 2 Daya dan Gerakan
Daya ialah kuantiti fizik yang boleh mengubahkan keadaan pegun atau gerakan seragam suatu objek apabila daya bertindak ke atas suatu objek.
Kesan Daya
• Bentuk
• Saiz
• Laju
• Arah objek yang bergerak
Example 1:
ITeach – Physics Form 4
Understanding The Effect Of ForceChapter 2 Forces And Motion
Balanced Forces
When two of more forces acts on an object produces no nett force, then the forces are said to be balanced.
When balanced forces act on an object the object either
remains at rest moves with constant velocity
Example 2: Example 3:
Contoh 1:
ITeach – Fizik Tingkatan 4
Memahami Kesan DayaBab 2 Daya dan Gerakan
Daya-daya yang Seimbang
Apabila dua atau lebih daya yang bertindak pada satu objek memusnahkan antara satu sama lain, daya paduan yang bertindak pada objek itu adalah seimbang.
Apabila daya-daya seimbang bertindak ke atas suatu objek,
objek itu akan
kekal dalam keadaan rehat Bergerak dalam kelajuan tetap
Contoh 2: Contoh 3:
ITeach – Physics Form 4
Understanding The Effect Of ForceChapter 2 Forces And Motion
When two or more forces acting on an object are not balanced,
Unbalanced Forces
Newton’s Second Law of motion
• The mathematical representation of Newton’s Second Law of Motion is
Fnet = ma
there will be a net force acting on the object.
the acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
ITeach – Fizik Tingkatan 4
Memahami Kesan DayaBab 2 Daya dan Gerakan
Apabila dua atau lebih dari dua daya daya yang bertindak ke atas suatu objek adalah tidak seimbang
Daya-daya yang Tidak Seimbang
Hukum Gerakan Kedua Newton
• Hukum Gerakan Kedua Newton :
Fnet = ma
Daya paduan bukan sifar
Kadar perubahan momentum suatu objek adalah berkadar langsung dan dalam arah yang sama dengan daya paduan yang bertindak ke atasnya.
ITeach – Physics Form 4
Understanding The Effect Of ForceChapter 2 Forces And Motion
Example 1
20 N4 N
5 kg
Net force acting of object, Fnet = 20 + 4 = 24 N to the right
According to Newton’s Second Law of Motion,
24 = (5)a
Therefore acceleration, a = 24/5 = 4.8 ms-2
20 N 4 N5 kg
Fnet = 20 – 4 = 16 N to the right
According to Newton’s Second Law of Motion,
Fnet = ma
16 = (5)a
Therefore acceleration, a = 16/5 = 3.2 ms-2
Fnet = ma
Example 2
ITeach – Fizik Tingkatan 4
Memahami Kesan DayaBab 2 Daya dan Gerakan
Contoh 1
20 N4 N
5 kg
Daya paduan pada obejk, Fnet = 20 + 4 = 24 N ke kanan
Mengikut Hukum Gerakan Kedua Newton
24 = (5)a
Pecutan, a = 24/5 = 4.8 ms-2
20 N 4 N5 kg
Fnet = 20 – 4 = 16 N ke kanan
Mengikut Hukum Gerakan Kedua Newton,
Fnet = ma
16 = (5)a
Pecutan, a = 16/5 = 3.2 ms-2
Fnet = ma
Contoh 2
There are 2 forces act on the system
• The man’s weight, W (downward)
• Normal reaction, R, act upward
ITeach – Physics Form 4
Understanding The Effect of ForceChapter 2 Forces and Motion
A man standing on a weighing scale in a lift.
Lift
W
R
Application of Balanced and Unbalanced Forces
Situation 1 : The lift stays stationary or moving with constant velocity
Situation 2 : The lift accelerate upward with acceleration a.
Situation 3 : The lift accelerate downward with acceleration a.
Weighing machine
Lift
Terdapat 2 daya bertindak pada sistem
• Berat lelaki, W (ke bawah)
• Tindak balas normal, R, bertindak ke atas
ITeach – Fizik Tingkatan 4
Memahami Kesan DayaBab 2 Daya dan Gerakan
Seorang lelaki berdiri di atas mesin penimbang di dalam sebuah lif.
Lif
W
R
Kegunaan Daya-daya Seimbang dan Tidak Seimbang
Situasi 1 : Lif pegun atau bergerak dengan halaju tetap.
Situasi 2 : Lif memecut ke atas dengan pecutan a.
Situasi 3 : Lif memecut ke bawah dengan pecutan a.
Mesin penimbang
Lif
Chapter 2 Forces And Chapter 2 Forces And MotionMotion
2.1 Arah Mata Angin
ITeach – Physics Form 4
2.6 Understanding Impulse And Impulsive Force
Chapter 2 Forces and Motion
Analysing Momentum
ITeach – Physics From 4
Impulse
Impulse is defined as the change of momentum of an object, that isimpulse = final momentum – initial momentum
= mv - mu
impulse = final momentum – initial momentum
Example
= mv - mu
= (2)(4) – (2)(2) = 8 – 4
= 4 kg ms-1
2 kg
4 ms-1
2 kg
2 ms-1
before after2 kg
4 ms-1
Bab 2 Daya dan Gerakan
Memahami Impuls dan Daya Impuls
ITeach – Fizik Tingkatan 4
Impuls
Impuls = Momentum akhir – Momentum awal= mv - mu
Impuls = Momentum akhir – Momentum awal
Contoh
= mv - mu
= (2)(4) – (2)(2) = 8 – 4
= 4 kg ms-1
2 kg
4 ms-1
2 kg
2 ms-1
sebelum selepas2 kg
4 ms-1
Impuls ditakrifkan sebagai perubahan momentum suatu objek.
ITeach – Physics Form 4
Understanding Impulse And Impulsive ForceChapter 2 Forces And Motion
Impulsive Force
a strong force that acts within a short period of time between colliding objects.
Hitting nail with a hammer
Hitting a baseball with a baseball bat
Car involved in an accident
is defined as the rate of change of momentum in a collision :
Impulsive force , F = (mv – mu) ÷ t
Examples where impulsive force is produced
ITeach – Fizik Tingkatan 4
Memahami Impuls dan Daya ImpulsBab 2 Daya dan Gerakan
Daya Impuls
Suatu daya kuat yang bertindak dalam jangka masa pendek antara objek-objek yang berlanggar.
Memukul paku menggunakan
penukul
Memukul bola besbol dengan pemukul bola
besbol
Kereta terlibat dalam kemalangan
Ditakrifkan sebagai kadar perubahan momentum dalam pelanggaran :
Daya impuls , F = (mv – mu) ÷ t
Contoh-contoh daya impuls dihasilkan
ITeach – Physics Form 4
Understanding Impulse And Impulsive ForceChapter 2 Forces And Motion
Impulsive Force – Reducing The Impulsive Force
Large impulsive force may be harmful, therefore in certain situations impulsive force needs to be reduced.
Impulsive force can be reduced by increasing the time of impact between two colliding objects.
ITeach – Fizik Tingkatan 4
Memahami Impuls dan Daya ImpulsBab 2 Daya dan Gerakan
Daya Impuls – Mengurangkan Kesan Daya Impuls
Daya impuls yang besar adalah merbahaya, jadi daya impuls perlu dikurangkan dalam situasi yang tertentu.
Daya impuls boleh dikurangkan dengan memanjangkan masa pelanggaran antara objek-objek yang berlanggar.
ITeach – Physics Form 4
Understanding Impulse And Impulsive ForceChapter 2 Forces And Motion
High Jump – Reducing The Impulsive Force
• A mattress is placed at the landing area in a high jump event.
• When the high jumper lands on the mattress, the mattress compresses and increases the time taken for the high jumper to stop, thus increasing the time of impact and reducing the impulsive force.
• This will prevent serious injury on the high jumper .
ITeach – Fizik Tingkatan 4
Memahami Impuls dan Daya ImpulsBab 2 Daya dan Gerakan
Lompat Tinggi – Mengurangkan Kesan Daya Impuls
• Sebuah tilam diletakkan pada tempat mendarat dalam acara lompat tinggi
• Apabila atlet mendarat pada tilam, tilam akan mampat dan memanjangkan masa bagi atlet untuk berhenti, jadi masa yang panjang semasa hentaman dapat mengurangkan daya impuls.
• Ini dapat mengurangkan kecederaan atlet lompat tinggi.
• The bonnet of a car is soft and is able to crumple easily.
• When a collision occurs, the bonnet gets crumpled and this increases the time taken for the car to stop (increasing the time of impact) thereby reducing the impulsive force on the car.
• This will prevent the passengers of the car from suffering serious injuries.
ITeach – Physics Form 4
Understanding Impulse And Impulsive ForceChapter 2 Forces And Motion
Impulsive Force - Reducing The Impulsive Force
• Bonet kereta lembut dan mudah kemek.
• Apabila pelanggaran berlaku, bonet menjadi kemek dan ini memanjangkan msa untuk kereta berhenti (memanjangkan masa pelanggaran). Masa pelanggaran yang panjang dapat mengurangkan daya impuls pada kereta.
• Ini dapat menghalang penumpang kereta daripada mendapat kecederaan yang serius.
ITeach – Fizik Tingkatan 4
Memahami Impuls dan Daya ImpulsBab 2 Daya dan Gerakan
Daya Impuls – Mengurangkan Daya Impuls
Chapter 2 Forces And Chapter 2 Forces And MotionMotion
2.1 Arah Mata Angin
ITeach – Physics Form 4
2.7 Safety Features In Vehicles
ITeach – Physics Form 4
Safety Features In VehiclesChapter 2 Forces And Motion
Safety features in cars are to reduce the damage to the cars and to reduce serious injuries to passengers caused by high impulsive force during collision.
Front bumper/Rear bumper : To absorb soft impact preventing damage to car
Front and rear crumple zones : Easily crushed to increase time of impact and hence decreases the magnitude of the impulsive force.Seat belt : Hold the passenger back preventing the passenger for being moving forward due to inertia
Importance Of Safety Features In A Car
Windscreen : Made of shatter-proof glass that will not break easily thus reducing injuries to passengers
Headrest : Prevents passengers from serious neck injuries.
Passenger safety case : Frame of car is reinforced to protect the passengers from injuries. Padded dashboard : Increases time of impact thus reducing impulsive force on passenger crashing onto the dashboard.
Steering wheel : Soft and easily crumpled, prevent driver from serious injuries to the head or chest during collision
Front bumperRear bumper
Front bumper/Rear bumper : To absorb soft impact preventing damage to carFront bumper/Rear bumper : To absorb soft impact preventing damage to car
Front and rear crumple zones : Easily crushed to increase time of impact and hence decreases the magnitude of the impulsive force.
Rear crumple zone
Front and rear crumple zones : Easily crushed to increase time of impact and hence decreases the magnitude of the impulsive force.
Seat belt
Windscreen
Headrests
Seat belt : Hold the passenger back preventing the passenger for being moving forward due to inertia
Seat belt : Hold the passenger back preventing the passenger for being moving forward due to inertia
Windscreen : Made of shatter-proof glass that will not break easily thus reducing injuries to passengers
Windscreen : Made of shatter-proof glass that will not break easily thus reducing injuries to passengers
Headrest : Prevents passengers from serious neck injuries. Headrest : Prevents passengers from serious neck injuries.
Passenger safety case
Padded dashboard
Steering wheel
Passenger safety case : Frame of car is reinforced to protect the passengers inside from injuries.
Passenger safety case : Frame of car is reinforced to protect the passengers from injuries.
Padded dashboard : Increases time of impact thus reducing impulsive force on passenger crashing onto the dashboard.
Padded dashboard : Increases time of impact thus reducing impulsive force on passenger crashing onto the dashboard.
Steering wheel : Soft and easily crumpled, prevent driver from serious injuries to the head or chest during collision
Steering wheel : Soft and easily crumpled, prevent driver from serious injuries to the head or chest during collision
Front crumple zone
ITeach – Fizik Tingkatan 4
Ciri Keselamatan dalam KeretaBab 2 Daya dan Gerakan
Ciri keselamatan dalam kereta dapat mengurangkan kerosakan kereta dan mengelakkan kecederaan yang serius pada penumpang yang disebabkan oleh daya impuls semasa pelanggaran.
Bamper depan/belakang : Untuk menyerap hentaman dan menghalang kerosakan kereta
Zon remuk depan dan belakang : Mudah remuk untuk memanjangkan masa pelanggaran dan mengurangkan daya impuls
Tali pinggang : Memegang penumpang supaya penumpang tidak terhumban ke hadapan disebabkan inersia.
Kepentingan Ciri Keselamatan dalam Kereta
Cermin depan: Dibuat daripada kaca tidak berkecai yang akan mengurangkan kecederaan penumpang.
Penahan kepala: Menghalang penumpang daripada kecederaan di leher.
Sarung keselamatan penumpang : Bingkai kereta dibuat dengan kukuh untuk melindungi penumpang daripada kecederaan.Pad papan pemuka : Meningkatkan masa hentaman dan mengurangkan daya impuls pada penumpang.
Stereng kereta : Lembut dan mudah remuk, menghalang pemandu daripada mendapat kecederaan yang serius pada kepala atau dada.
Bamper hadapanBamper belakang
Bamper depan/belakang : Untuk menyerap hentaman dan menghalang kerosakan keretaBamper depan/belakang : Untuk menyerap hentaman dan menghalang kerosakan keretaZon remuk depan dan belakang : Mudah
remuk untuk memanjangkan masa pelanggaran dan mengurangkan daya impuls
Zon remuk belakang
Zon remuk depan dan belakang : Mudah remuk untuk memanjangkan masa pelanggaran dan mengurangkan daya impuls
Tali pinggang
Cermin depan
Penahan kepala
Tali pinggang : Memegang penumpang supaya penumpang tidak terhumban ke hadapan disebabkan inersia.Tali pinggang : Memegang penumpang supaya penumpang tidak terhumban ke hadapan disebabkan inersia.
Cermin depan: Dibuat daripada kaca tidak berkecai yang akan mengurangkan kecederaan penumpang.
Cermin depan: Dibuat daripada kaca tidak berkecai yang akan mengurangkan kecederaan penumpang.
Penahan kepala: Menghalang penumpang daripada kecederaan di leher.
Penahan kepala: Menghalang penumpang daripada kecederaan di leher.
Sarung keselamatan penumpang
Pad papan pemuka
Stereng kereta
Sarung keselamatan penumpang : Bingkai kereta dibuat dengan kukuh untuk melindungi penumpang daripada kecederaan.
Sarung keselamatan penumpang : Bingkai kereta dibuat dengan kukuh untuk melindungi penumpang daripada kecederaan.
Pad papan pemuka : Meningkatkan masa hentaman dan mengurangkan daya impuls pada penumpang.
Pad papan pemuka : Meningkatkan masa hentaman dan mengurangkan daya impuls pada penumpang.Stereng kereta : Lembut dan mudah remuk, menghalang pemandu daripada mendapat kecederaan yang serius pada kepala atau dada.
Stereng kereta : Lembut dan mudah remuk, menghalang pemandu daripada mendapat kecederaan yang serius pada kepala atau dada.
Zon remuk hadapan
Chapter 2 Forces And Chapter 2 Forces And MotionMotion
2.1 Arah Mata Angin
ITeach – Physics Form 4
2.8 Understanding Gravity
ITeach – Physics Form 4
Understanding gravityChapter 2 Forces And Motion
Acceleration Due To Gravity
All objects are able stay on the surface of the Earth or fall to the ground due to the gravitational force that pulls them towards the centre of the Earth.
Coconut falling from a coconut tree
Satellite orbiting the earthAble to stay on the surface of the earth
ITeach – FiziK Tingkatan 4
Memahami GravitiBab 2 Daya dan Gerakan
Graviti
Semua objek dapat berdiri tegak di permukaan Bumi atau jatuh ke tanah disebabkan oleh daya graviti yang menarik semua objek ke pusat Bumi.
Buah kelapa jatuh dari pokok kelapa
Satellit mengorbit BumiManusia dapat berdiri di permukaan Bumi
ITeach – Physics Form 4
Understanding gravityChapter 2 Forces And Motion
Gravitational pull of the earth causes an object to accelerate at a constant rate as it falls.
The acceleration is known as the acceleration due to gravity, represented by the symbol ‘g’.
The acceleration due to gravity of the earth, g = 9.81 ms-2 (~ 10 ms-2).This means that the speed of a falling object increases by 10 ms-1 every 1 second as it falls to the surface of the earth.
Acceleration Due To Gravity
0 m/s → 0 s 10 m/s → 1 s 20 m/s → 2 s
30 m/s → 3 s
40 m/s → 4 s
50 m/s → 5 s
ITeach – Fizik Tingkatan 4
Memahami GravitiBab 2 Daya dan Gerakan
Tarikan daya graviti menyebabkan objek memecut pada kadar malar ketika objek bergerak jatuh ke tanah.
Pecutan ini dikenali sebagai pecutan graviti , diwakili oleh simbol ‘g’.
Pecutan graviti, g = 9.81 ms-2 (~ 10 ms-2). Laju bagi objek yang sedang jatuh ke permukaan Bumi meningkat sebanyak 10 ms-1 setiap 1 saat.
Pecutan Disebabkan Oleh Graviti
0 m/s → 0 s 10 m/s → 1 s 20 m/s → 2 s
30 m/s → 3 s
40 m/s → 4 s
50 m/s → 5 s
ITeach – Physics Form 4
Understanding gravityChapter 2 Forces And Motion
Weight
Weight of an object is defined as the gravitational force that acts on the object.
Weight, W = mass × acceleration due to gravity = mg
Example
Note : To calculate the weight of an object, the mass must be measured in kilogram while the acceleration due to gravity in units of ms-2
• A boy of mass 55 kg have a weight of (55)(10) = 550 Newton
• The weight of a 60 gram pencil is (60/1000)×(10) = 0.6 Newton
Note : The acceleration due to gravity on the surface of the moon is 1/6 the acceleration due to gravity on the surface of the earth
The acceleration due to gravity on the moon is about 1.66 ms-2
ITeach – Fizik Tingkatan 4
Memahami GravitiBab 2 Daya dan Gerakan
Berat
Berat ialah daya yang bertindak ke atas jisim sesuatu objek oleh tarikan Bumi.
Berat, W = Jisim × Pecutan graviti = mg
Contoh
Nota : Untuk mengira berat sesuatu objek, jisim mesti dikira dalam kilogram dan pecutan graviti dalam unit ms-2
• Seorang budak dengan jisim 55 kg mempunyai berat (55)(10) = 550 Newton
• Berat bagi 60 gram pensel ialah (60/1000)×(10) = 0.6 Newton
Nota : Pecutan graviti pada permukaan bulan adalah 1/6 daripada pecutan graviti di permukaan Bumi.
Pecutan graviti di permukaan Bulan ialah 1.66 ms-2
ITeach – Physics Form 4
Understanding gravityChapter 2 Forces And Motion
The Differences Between Mass And Weight
Mass, m Weight, W
The amount of matter in an object The gravitational force acting on an object
Base quantity Derived quantity
S I Unit : kilogram S I Unit : Newton
Value is constant everywhere. Value depends on the acceleration due to gravity.
Scalar quantity Vector quantity
Example
An object of mass 10kg on earth also has a mass of 10kg on the moon.
Example
An object weights 600 N on earth will only weigh 100N on the moon.
ITeach – Fizik Tingkatan 4
Memahami GravitiBab 2 Daya dan Gerakan
Perbezaan Antara Jisim Dengan Berat
Jisim, m Berat, W
Jumlah jirim yang ada dalam sesuatuobjek
Daya yang bertindak ke atas sesuatu objek
Kuantiti asas Kuantiti terbitan
S I Unit : kilogram S I Unit : Newton
Nilai tetap Nilai bergantung kepada pecutan graviti.
Kuantiti skalar Kuantiti vektor
Contoh
Jisim suatu objek di Bumi ialah 10 kg. Jisim objek itu di Bulan juga adalah 10 kg.
Contoh
Berat suatu objek di Bumi ialah 600 N. Berat objek itu di Bulan ialah 100 N.
Chapter 2 Forces And Chapter 2 Forces And MotionMotion
2.1 Arah Mata Angin
ITeach – Physics Form 4
2.9 Analysing Forces In Equilibrium
ITeach – Physics Form 4
Analysing Forces In EquilibriumChapter 2 Forces And Motion
When the forces acting on an object is in equilibrium, then no net (resultant) force acts on the object.
Forces In Equilibrium
Example
A pile book on a tableA rifle hanging on a wall
A car moving with constant velocity An object resting on an inclined plane
The object will either be at rest (stationary) or moves with constant velocity.
ITeach – Fizik Tingkatan 4
Menganalisis Daya - daya KeseimbanganBab 2 Daya dan Gerakan
Apabila daya-daya yang bertindak pada suatu objek adalah seimbang, maka tiada daya paduan bertindak pada objek itu.
Daya – daya Keseimbangan
Contoh
Buku-buku yang bertindih di atas mejaSenapang digantung pada dindingl
Kereta bergerak dengan halaju seragam Suatu objek dalam keadaan rehat pada satah condong
Objek itu akan berada pada keadaan rehat (pegun) atau bergerak pada halaju tetap.
ITeach – Physics Form 4
Analysing Forces In EquilibriumChapter 2 Forces And Motion
Two parallel forces are in equilibrium if the two forces have the same magnitude but act in opposite directions.
Forces In Equilibrium – Parallel Forces
Examples
T F
F
T
drag
forward thrust
A car moving with constant velocity
driving force frictional forces
The driving force and the frictional force are in equilibrium
An aeroplane cruising at constant velocity
Forward thrust and drag are in equilibrium
ITeach – Fizik Tingkatan 4
Menganalisis Daya – daya KeseimbanganBab 2 Daya dan Gerakan
Dua daya-daya selari adalah seimbang jika kedua-dua daya mempunyai magnitud yang sama tetapi bertindak pada arah yang berlainan.
Daya – daya Keseimbangan – Daya – daya Selari
Contoh
T F
F
T
seretan
Tujahan ke hadapan
Sebuah kerera bergerak dengan halaju seragam
Daya memandu
Daya geseran
Daya memandu dan daya geseran dalam keadaan seimbang
Sebuah kapal terbang bergerak pada halaju seragam
Tujahan ke hadapan dan seretan berada dalam keadaan seimbang
The diagram below shows three forces P, Q and R acting in a system.The three forces are in equilibrium.
ITeach – Physics Form 4
Analysing Forces In EquilibriumChapter 2 Forces And Motion
Forces In Equilibrium - Three Non-Parallel Forces
wallwallR
QP
90°
30°
30°
P
RQ
A closed triangle will be obtained if the three forces are drawn end-to-end
Rajah di bawah menunjukkan tiga daya P, Q dan R bertindak pada satu sistem. Ketiga – tiga daya berada dalam keadaan seimbang.
ITeach – Fizik Tingkatan 4
Menganalisis Daya – daya KeseimbanganBab 2 Daya dan Gerakan
Daya – daya Keseimbangan – Tiga Daya- daya Tidak Selari
DindingDindingR
QP
90°
30°
30°
P
RQ
Sebuah segitiga akan diperolehi jika garisan pada ketiga-tiga daya disambungkan
ITeach – Physics Form 4
Analysing Forces In EquilibriumChapter 2 Forces And Motion
Resultant Force – Parallelogram Of Forces
When two force P and Q acts on a object, the resultant force F, is represented by the diagonal of a parallelogram drawn using the forces P and Q.
Example : The resultant of the forces P and Q can be obtained as shown
If drawn to scale, the length of the diagonal OC represents the magnitude of the resultant force while the angle shows the direction of the resultant force.
PA0
0P
Q
B
0P
B C
P
0P
PB C
Aθ
ITeach – Fizik Tingkatan 4
Menganalisis Daya-daya KeseimbanganBab 2 Daya dan Gerakan
Hasil Campur Daya-daya – Segiempat Selari
Apabila dua daya P dan Q bertindak pada suatu objek, hasil campur daya F, diwakili pepenjuru segiempat selari.
Contoh : Hasil campur daya-daya P dan Q boleh diperolehi seperti dibawah:
Jika dilukis mengikut skala, panjang pepenjuru OC mewakili magnitud hasil campur daya-daya manakala sudut menunjukkan arah hasil campur daya-daya.
PA0
0P
Q
B
0P
B C
P
0P
PB C
Aθ
Resolution Of Forces
ITeach – Physics Form 4
Analysing Forces In EquilibriumChapter 2 Forces And Motion
A force can be resolved into two components, that is, the two components, that is, the
horizontal component, Fx, and the
Vertical component, Fy
θFx = F cosθ
Fy = F sinθF
Leraian Daya
ITeach – Fizik Tingkatan 4
Menganalisis Daya-daya KeseimbanganBab 2 Daya dan Gerakan
Satu daya boleh dileraikan kepada 2 komponen iaitu
Komponen ufuk, Fx, dan
Komponen tegak, Fy
θFx = F cosθ
Fy = F sinθF
The force that moves the boat horizontally is the horizontal component of the force F = 500N
ITeach – Physics Form 4
Analysing Forces In EquilibriumChapter 2 Forces And Motion
Resolution Of Forces – Horizontal Component
The horizontal component, Fx, is the “effective” force that moves the object in the horizontal direction.
Example
That is, Fx = F cos 15° = (550)(0.9659) = 531.3N
boat
river
ropeF = 550 N,
15°
Daya yang menggerakkan bot secara mengufuk adalah komponen ufuk daya F = 500N
ITeach – Fizik Tingkatan 4
Menganalisis Daya-daya KeseimbanganBab 2 Daya dan Gerakan
Leraian Daya – Komponen Ufuk
Komponen ufuk, Fx, adalah daya yang menggerakkan objek pada arah mengufuk.
Contoh
Fx = F cos 15° = (550)(0.9659) = 531.3N
bot
sungai
taliF = 550 N,
15°
Chapter 2 Forces And Chapter 2 Forces And MotionMotion
2.1 Arah Mata Angin
ITeach – Physics Form 4
2.10 Understanding Work, Energy, Power And Efficiency
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
Work Done
Work is a kind of energy transfer.
Work is done if an object acted upon by a force moves in the direction of the force.
Work done, W = applied force, F × distance moved in the direction of the applied force, s
Therefore work done, W =
F F
s
Fs
ITeach – Fizik Tingkatab 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanBab 2 Daya dan Gerakan
Kerja Dilakukan
Kerja ialah satu jenis pemindahan tenaga.
Kerja dilakukan jika suatu objek bertindak melalui daya dan bergerak pada arah daya.
Kerja dilakukan, W = Daya, F × sesaran dalam arah daya itu, s
Kerja dilakukan, W =
F F
s
F s
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
Work Done
If the applied force makes an angle with the direction of motion of the object, as shown
work done,W = horizontal component of the force × displacement
work done, W = (F cos) (s)
= Fs cos
The unit of work is Newton meter (N m) of Joule (J)
θ θ
F F
s
ITeach – Fizik Tingkatan 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanBab 2 Daya dan Gerakan
Kerja Dilakukan
Jika daya dikenakan membuat sudut pada arah objek bergerak, seperti dibawah:
Kerja dilakukan,W = Komponen ufuk daya × Sesaran
Kerja dilakukan, W = (F kos ) (s)
= Fs kos
Unit kerja ialah Newton meter (N m) atau joule (J)
θ θ
F F
s
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
Examples Of Work Done
Pushing a shopping cart
Car barking. Work is done by the brakes.
Weightlifting
ITeach – Fizik Tingkatan 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanBab 2 Daya dan Gerakan
Contoh Kerja Dilakukan
Menolak troli Kereta membrek. Kerja dilakukan oleh brek.
Angkat berat
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
The object that is acted upon by a force remains stationary.
The direction of motion of the object is perpendicular to the applied force.
Examples Of Work Not Done
Man pushing a wall
Waiter walking towards the diner
ITeach – Fizik Tingkatan 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanBab 2 Daya dan Gerakan
Objek yang ditindakkan oleh suatu kekal berada dalam keadaan pegun.
Arah pergerakan objek berserenjang dengan daya yang dikenakan.
Contoh Kerja Tidak Dilakukan
Seorang lelaki menolak dinding
Pelayan berjalan ke arah meja
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
Energy
Energy is the ability of an object to do work.
When work is done on an object, the object gains energy.
ITeach – Fizik Tingkatan 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanBab 2 Daya dan Gerakan
Tenaga
Tenaga ialah keupayaan sesuatu objek untuk melakukan kerja.
Apabila kerja dilakukan pada suatu objek, objek mendapat tenaga.
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
Kinetic Energy
Kinetic energy is the energy possesses by an object because of its motion.
This means that any object that moves have kinetic energy.
The magnitude of the kinetic energy possessed by an object of mass m kilogram moving with a speed of v meters per second is
Examples a moving car
A bowling ball rolling towards the bowling pins
An electron orbiting an atom
Kinetic energy = ½ m v2
ITeach – Fizik Tingkatan 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanBab 2 Daya dan Gerakan
Tenaga Kinetik
Tenaga kinetik ialah tenaga yang disebabakan oleh gerakan.
Sebarang objek yang bergerak mempunyai tenaga kinetik.
Tenaga kinetik bagi suatu objek dengan jisim m kilogram dan bergerak dengan laju v meter per saat diberi oleh formula
Contoh Kereta yang sedang bergerak
Bola boling bergerak ke arah lorong boling
Elektron mengorbit atom
Tenaga Kinetik = ½ m v2
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
Gravitational Potential Energy
Potential energy is energy that is stored in an object
When work is done in lifting the box to a certain height above the ground, the box gains gravitational potential energy.The gravitational potential energy of an object depends on its mass and its height above the ground. Gravitational potential energy = mgh
g = acceleration due to gravity Where m = mass
h = vertical height of object above the ground
force
displacement
Work is done
ITeach – Fizik Tingkatan 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanBab 2 Daya dan Gerakan
Tenaga Keupayaan Graviti
Tenaga keupayaan ialah tenaga yang diperoleh oleh suatu objek yang disebabkan oleh ketinggiannya dalam medan graviti.
Kotak mendapat tenaga keupayaan graviti apabila kerja mengangkat kotak dilakukan hingga ke satu aras ketinggian di atas permukaan Bumi.Tenaga keupayaan graviti bergantung kepada jisim dan ketinggian di atas permukaan Bumi.Tenaga keupayaan graviti = mgh
g = pecutan disebabkan oleh gravitiDimana m = jisim
h =ketinggian objek di atas permukaan Bumi
Daya
Sesaran
Kerja dilakukan
The stretched rubber band of the catapult stores energy
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
Elastic Potential Energy
Elastic potential energy is the energy stored in an elastic object that is compressed or stretched.
A compressed spring stores energy
Gelang getah yang diregangkan mempunyai tenaga keupayaan kenyal
ITeach – Fizik Tingkatan 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanBab 2 Daya dan Gerakan
Tenaga Keupayaan Kenyal
Tenaga keupayaan kenyal ialah tenaga yang tersimpan dalam suatu bahan kenyal yang di dimampatkan atau diregangkan.
Spring yang dimampatkan mempunyai tenaga keupayaan kenyal
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
Other Common Forms Of Energy
Chemical energy in a dry cell
Heat energy
Light energy
Electrical energy
Sound energy
ITeach – Fizik Tingkatan 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanBab 2 Daya dan Gerakan
Bentuk Tenaga yang Lain
Tenaga kimia pada sel kering
Tenaga haba
Tenaga cahaya
Tenaga elektrik
Tenaga bunyi
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
Examples:
Chemical energy to light heat
Gravitational potential energy to kinetic energy
Gravitational potential energy to electrical energy
Principle Of Conservation Of Energy
The amount of energy in the universe is constant.
Energy cannot be created nor it can be destroyed.
The Principle of Conservation of Energy states that energy can neither be created nor destroyed but energy changes from one form to another.
ITeach – Fizik Tingkatan 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanKuasa 2 Daya dan Gerakan
Contoh :
Tenaga kimia ke tenaga haba
Tenaga keupayaan graviti kepada tenaga kinetik
Tenaga keupayaan graviti kepada tenaga elektrik
Prinsip Keabadian Tenaga
Jumlah tenaga di alam semesta adalah tetap.
Tenaga tidak boleh dicipta atau dimusnahkan.
Prinsip Keabadian Tenaga menyatakan tenaga boleh berubah daripada satu bentuk ke bentuk lain tetapi tenaga tidak boleh dicipta atau dimusnahkan.
ITeach – Physics Form 4
Understanding Work, Energy, Power And EfficiencyChapter 2 Forces And Motion
Power
Power, P, is the rate at which work is done or energy is transferred.
Power, P =Work done, W or Energy, E
Time taken,t
Power, P = E/t
The unit of power is Joule per second (Js-1) or the Watt (W)
Example : An electric bulb rated 50 W used 50 Joules of electrical energy per second
ITeach – Fizik Tingkatan 4
Memahami Kerja, Tenaga, Kuasa dan KecekapanBab 2 Daya dan Gerakan
Kuasa
Kuasa, P, ialah kadar kerja dilakukan atau pemindahan tenaga.
Kuasa, P =Kerja dilakukan, W atau Tenaga, E
Masa diambil,t
Kuasa, P = E/t
Unit bagi kuasa ialah Joule per saat (Js-1) atau Watt (W)
Contoh : Sebiji mentol elektrik pada kadar 50 W menggunakan 50 joule tenaga elektrik setiap satu saat.
Chapter 2 Force And MotionChapter 2 Force And Motion
ITeach – Physics Form 4
2.11 2.11 Understanding ElasticityUnderstanding Elasticity
ITeach – Physics Form 4
Understanding ElasticityChapter 2 Force And Motion
ElasticityAn object is said to be elastic if the object returns to its original shape when the force
acting on it is removed.
Example
Spring Elastic Band
ITeach – Fizik Tingkatan 4
Memahami KekenyalanBab 2 Daya dan Gerakan
KekenyalanSuatu objek dikatakan kenyal jika objek itu kembali ke bentuk asal apabila daya yang
bertindak ke atas objek dialihkan.
Contoh
Spring Gelang getah
Spring mendapat tenaga keupayaan kenyal apabila ditekan atau diregang
pegun
dimampat diregang
Tenaga keupayaan kenyal
ITeach – Physics Form 4
Understanding ElasticityChapter 2 Force And Motion
Hooke’s Law
Hooke’s Law states that the extension of a spring is directly proportional to the stretching force that acts on it provided the elastic limit is not exceeded.
The elastic limit is the maximum force that can be applied to the spring before it ceases to be elastic.
metre rule
retort stand
load
ITeach – Fizik Tingkatan 4
Memahami KekenyalanBab 2 Daya dan Gerakan
Hukum Hooke
Hukum Hooke menyatakan pemanjangan spring adalah berkadar terus dengan daya yang dikenakan dengan syarat daya yang dikenakan tidak melebihi had kenyal.
Had kenyal ialah daya pemanjangan maksimum yang boleh dikenakan ke atas spring sebelum spring menjadi tidak kenyal dan pemanjangannya menjadi kekal.
Pembaris meter
Kaki retort
Beban
Beyond E (E to P)Elastic limit is exceeded. If the stretching force is removed, the spring suffers permanent damage and will be deformed.
Point E : elastic limit
ITeach – Physics Form 4
Understanding ElasticityChapter 2 Force And Motion
Hooke’s Law - Graph of applied force against extension
The graph of the stretching force against the extension produced by a spring
Line OE : Hooke’s law is obeyed. If the stretching force is removed, the spring will return to its original length.
PE
F
OX
F = kxspring obeyingHooke’s law spring not
obeying Hooke’s law
Melebihi E (E hingga P)Melebihi had limit. Jika daya yang dikenakan dialih, pemanjangan spring akan kekal dan spring akan rosak.
Titik E : Had kenyal
ITeach – Fizik Tingkatan 4
Memahami KekenyalanBab 2 Daya dan Gerakan
Hukum Hooke - Graf Daya yang Dikenakan Melawan Daya Pemanjangan
Graf daya yang dikenakan melawan pemanjangan spring dihasilkan oleh spring
Garis OE : Hukum Hooke tidak dipatuhi. Jika daya yang dikenakan dialihkan, spring akan kembali ke panjang asal.
PE
F
OX
F = kxspring mematuhiHukum Hooke Spring tidak
mematuhi Hukum Hooke
ITeach – Physics Form 4
Understanding ElasticityChapter 2 Force And Motion
Hooke’s Law - The elastic constant or spring constant
• When Hooke’s Law is obeyed, the graph of applied force against extension is a straight line through the origin.
• Hooke’s Law states that F = kx where k is the spring constant.
• The gradient of the F-x graph gives the spring constant of the spring.
• The higher the spring constant, the stiffer (less elastic) is the spring and vice versa.
ITeach – Fizik Tingkatan 4
Memahami KekenyalanBab 2 Daya dan Gerakan
Hukum Hooke - Pemalar spring
• Apabila hukum Hooke dipatuhi, graf daya yang dikenakan melawan pemanjangan spring adalah suatu graf garis lurus.
• Hukum Hooke menyatakan F = kx dimana k ialah pemalar spring.
• Kecerunan graf F-x memberi nilai pemalar spring.
• Semakin tinggi nilai pemalar spring, semakin tegang (kurang kenyal) spring dan sebaliknya.
Daya, F / N
Pemanjangan spring, x / cm
ITeach – Physics Form 4
Understanding ElasticityChapter 2 Force And Motion
Length Short Long
F F
Diameter of spring coil Large diameter Small diameter
FF
Factors Stiff Less Stiff
Diameter of material of spring
Thin wire Thick wire
F F
Material used as spring
F F
copper spring
Steel spring
Arrangement of springs
Parallel Series
mm
Factors Affecting The Elasticity Of A Spring
PanjangDiameterkecilDawai tebalBersiriPendekDiameter
besarDawai nipisSelari Susunan springPanjangDiameter gegelung
springDiameter bahan springBahan yang digunakan
sebagai spring
ITeach – Fizik Tingkatan 4
Memahami KekenyalanBab 2 Daya dan Gerakan
F FFF
Faktor Tegang Kurang tegang
F FF F
Springkuprum
Spring besi
mm
Faktor yang Mempengaruhi Kekenyalan Spring
ITeach – Physics Form 4
Understanding ElasticityChapter 2 Force And Motion
Elastic Potential Energy
A stretched spring stores energy as elastic potential energy.
elastic potential energy stored in a spring.F / N
x / mo
area under the Force against extension graph.
=
2e kx
21Fx
21E
ITeach – Fizik Tingkatan 4
Memahami KekenyalanBab 2 Daya dan Gerakan
Tenaga Keupayaan
Kenyal Spring yang diregangkan menyimpan tenaga
sebagai tenaga keupayaan kenyal.
Tenaga keupayaan kenyal tersimpan dalam springF / N
x / mo
Luas dibawah graf daya melawan pemanjangan
spring.
=
2e kx
21Fx
21E
ITeach – Physics Form 4
Understanding ElasticityChapter 2 Force And Motion
Application Of Elasticity
Spring Mattress Shock absorber Spring balance Ammeter
ITeach – Fizik Tingkatan 4
Memahami KekenyalanBab 2 Daya dan Gerakan
Aplikasi Kekenyalan
Tilam spring Penyerap kejutan Penimbang spring Ammeter
The End
i - Teach