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1. MOMENTUM
1. Definisi momentum:
Hasil darab jisim dan halaju.
* Semua objek yang bergerak mempunyai momentum:
momentum = m x v
= 50kg x 5ms-1
= 250 kgms-1
2. Prinsip Meabadian Momentum:
Jumlah momentum adalah sentiasa malar jika tiada daya luar yang terlibat.
3. Keabadian momentum dalam perlanggaran antara dua objek:
PERLANGGARAN KENYAL PERLANGGARAN TIDAK KENYAL
Jumlah momentum = Jumlah momentum
sebelum perlanggaran selepas perlanggaran
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mu + mu = mv + mv mu + mu = (m + m) v
4. Pemuliharaan momentum dalam letupan:
J.momentum = J.momentum sebelum letupan selepas letupan 0 = mv + mv -mv = mv
5. Contoh letupan:
1. MOMENTUM
1. Definition of momentum:
Product of mass and velocity.
*All moving objects have momentum:
His momentum = m x v
= 50kg x 5ms-1
= 250 kgms-1
2. The POCOM (Principles of Conservation of Momentum)
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Total momentum is always constant if no external force involved in the system.
3. Conservation of momentum in collision between two objects:
ELASTIC COLLISION INELASTIC COLLISION
Total momentum before collision = Total momentum after collision
mu + mu = mv + mv mu + mu = (m + m)v
4. Conservation of momentum in explosion:
T.momentum = T.momentum before explosion after explosion 0 = mv + mv -mv = mv
5. Examples of explosion:
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2. Application of Resultant Force – Lift & Pulley System
1. Lift:
Calculate the lift acceleration upwards, a:
F – F = ma
R – W = ma
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800 – (70kg x 9.81) = 70a a = 1.62ms
-22. Pulley system – has 2 different resultant forces, but with similar rope tension, T:
For 10kg object:
F – F = ma
T – Fr = 10a
For 30kg object:
F – F = ma
W – T = 30a
3. Force Resolution – 1 Force & 2 Forces
1. One original force – split the force (100N) into vertical force (Fy) dan horizontal force (Fx).
Fx = 100 x cos 30 ° = 86.6N
Fy 100 x sin 30 ° = 50N
6 Question example:
Calculate horizontal force X:
X = 30N cos 10 = 30 x 0.985 = 29.5N
2. Splitting of two forces:
Total of horizontal forces to the right =
Fx + Fx Fx
10 x cos30 ° = 8.67N So,Fx + Fx = 8.67 + 11.28
= 19.95N Fx
12 x cos20 ° =11.28N
4. Application of Force Resolution – Inclined
Plane
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Important Points:
1. The original force is the object weight = W = mg 2. W is split into Fx & Fy
3. Use F – F = ma So, W sin30 – Fr = ma
4. W cos30 = R (because object is not moving vertically) 5. F is the force to hold the object. To find F, use formula:
F cos 30 = W sin 30
(no need to think, just know it :-D)
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5. Force Resolution App. – Hanging Object Aplikasi Leraian Daya – Objek Tergantung
Question/ soalan:
Calculate T1 & T2 Kira T1 & T2
Solution/ Penyelesaian
Split T2 into Fy & Fx/
Leraikan T2 kpd Fy & Fx
So/ maka,
100 = T2 sin30°
T2 = 200N
Fx = T1
So/ maka, Fx = T2 cos30°
= 200 X 0.87
T1 = 174N
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6. PRINSIP PASCAL
1. Penerangan:
Dalam sistem bendalir tertutup, tekanan diagihkan sama rata kepada semua bahagian bendalir.
2. Aplikasi - Sistem hidraulik:
Tekanan A = tekanan B Daya A = Daya B Luas A Luas B 6N = 3000N 2m
21000m
21P = 1P
Force modifier = Luas B/ Luas A = 1000m
2/ 2m
2= 500
Daya kecil digunakan...
Untuk mengangkat
beban yg
besar!
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The force is multiplied 500 times at the car!
3. Aplikasi 2 – Sistem Brek Hidraulik:
Ciri-Ciri Penjelasan Minyak sebagai
cecair brek.
Tidak mudah dimampatkan.
Lapisan brek tebal. Untuk menahan daya yang besar pada brek.
Luas kecil pada
silinder induk. Daya kecil pada silinder induk
menjana daya besar pada silinder roda.
Luas besar pada silinder roda.
Roda depan - Guna brek cakera.
Cakera brek lebih cekap daripada drum brek (melesapkan haba lebih banyak daripada brek dram.) Roda belakang –
Gunak brek dram.
7. ELECTROMOTIVE FORCE (EMF)/ DAYA GERAK ELEKTRIK (DGE)
1. What is emf?/ Apa itu dge?
Complete circuit = dry cell + conductor circuit Litar lengkap = sel kering + litar konduktor
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Energy/work used to move 1C of total charges in a complete circuit Tenaga/ kerja digunakan utk menggerakkan 1C cas dalam litar lengkap
2. Let’s compare potential difference and emf/ Jom bezakan beza keupayaan dan dge:
POTENTIAL DIFFERENCE EMF
Use energy to move 1C between 2 points in conductor
Use energy to move 1C in complete circuit
Symbol =
V
Symbol =Ɛ
*so, PD is a part of EMF/ maka, BK ialah sebahagian drpd DGE 3. Eksperiment to find out emf/ eksperiment utk mengira dge:
- adjust rheostat until ammeter reading zero / bulb turns off - now, voltmeter reading shows the emf
12 - selaraskan reostat hingga bacaan ammeter jadi sifar/ lampu padam
- sekarang, bacaan voltmeter menunjukkan dge 4. Graph:
Information from the graph/ maklumat daripada graf:
a. Graph shows linear form with negative gradient
Graf menunjukkan corak linear dengan kecerunan negatif b. y-intercept shows the emf, Ɛ (highest voltage possible) pintasan-y menunjukkan dge, Ɛ (nilai voltan paling tinggi) c. Gradient = y/x = V/I = r = internal resistance
Kecerunan = y/x = V/I = r = rintangan dalam r = resistance in the dry cell circuit
r= rintangan dalam litar sel kering
d. We can arrange the variables to find out the formula of emf Kita boleh susun pembolehubah utk mendapatkan formula dge:
Use linear graph formula,
y = mx + c
y = y axis
V
m = gradient
V/I = -r
x = x axis
I
c = y-intercept
Ɛ V = -Ir +Ɛ
Ɛ = V + Ir
13 5. How to calculate internal resistance / Cara kira rintangan dalam:
Dry cells arranged in a serial circuit Sel kering disusun secara litar siri
Arranged in paralled circuit Disusun secara litar selari
Total, r
Tr
T= r
1+ r
2+ r
3Total internal resistance, r
T1/r
T= 1/r
1+ 1/r
2+ 1/r
3 Advantage of arrangment/ kelebihan susunan- lower internal resistance/ rintangan dalam lebih rendah
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8. ELECTROMAGNETIC INDUCTION/ ARUHAN ELEKTROMAGNET
1. Describing the induction/ Huraian aruhan:
a. Move conductor across the magnetic field (relative motion happens) Gerakkan konduktor merentas medan magnet (gerakan relatif berlaku) b. We are changing or cutting the magnetic flux
Kita mengubah atau memotong fluks magnet
c. This will generate induction electromotive force (emf) Ini menjana daya gerak elaktrik (dge) aruhan
d. Induction EMF will generate induction current DGE aruhan menjana arus aruhan
2. Faraday Law/ Hukum Faraday:
“The higher the rate of cutting flux magnet, the higher the magnitude of induction EMF”
“Makin tinggi kadar pemotongan fluks magnet, makin tinggi
magnitud dge aruhan
”15 3. To determine the direction of induction current, we use Fleming’s Right Hand Rule
Utk menentukan arah arus aruhan, kita guna Petua Tangan Kanan Fleming
Faraday Law’s application – the faster we move wire, the higher the galvanometer reading!
Aplikasi Hukum Faraday – makin laju kita gerakkan dawai, makin besar bacaaan galvanometer!
4. For solenoid, we use Lenz Law to determined the direction of induction current/
Utk solenoid, kita gunakan Hukum Lenz utk menentukan arah arus aruhan
16 When we insert magnet, solenoid will have same pole with inserting magnet
Apabila kita masukkan magnet, solenoid akan mempunyai kutub sama dgn magnet yg masuk
When we pull out magnet, solenoid will have different pole
Apabila kita tarik keluar magnet, solenoid akan mempunyai kutub berbeza
*Use Right Hand Grip Rule to determine the direction of current in solenoid/
Guna Petua Genggaman Tangan Kanan utk menentukan arah arus dlm solenoid 5. How to increase the galvanometer reading?/ Cara meningkatkan bacaan
galvanometer?
Move magnet faster
Gerakkan magnet lebih pantas
Use stronger magnet
Guna magnet lebih kuat
Increase the number of wire turns in solenoid Tambahkan bilangan lilitan solenoid
9. DIOD SEMIKONDUKTOR (SEMICONDUCTOR DIODE)
1. Simbol & fungsi/ symbol & function
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Simbol diod/
Diode symbol Fungsi/
Function
Tukar arus ulang-alik (au) ke arus terus (at)
Convert alternating current (ac) to direct current (dc)
2. Sambungan diod/ Diode connection:
sambungan pincang depan forward bias connection
sambungan pincang songsang reverse bias connection
Arus mengalir → mentol menyala Current flows → light up
Arus tidak mengalir → tidak nyala Current doesn’t flow → no light
3. Rektifikasi = proses au ditukar ke at
2 jenis rektifikasi – gelombang separuh & gelombang penuh (Rectification = process of converting ac to dc
2 types – half-wave & full-wave)
A. Rektifikasi gelombang separuh
Half-wave rectification
18 Before Rec. After Rec.
Gelombang pertama First wave
= pincang hadapan = arus alir
= forward-bias = current flows
Gelombang kedua Second wave
= pincang songsang = tiada arus
= reverse-bias = no current flows
Rektifikasi gelombang penuh Full-wave rectification
Before Rec. After Rec.
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Gelombang pertama First wave
= pincang hadapan utk B & C
= Forward-bias for B
& C
Gelombang kedua Second wave
= pincang hadapan utk D & A
= Forward-bias for D
& A
4. Perataan = proses meratakan arus menggunakan kapasitor Smoothing = process of smoothing the current using capacitor
Meratakan litar gelombang separuh Smoothing the half-wave circuit
No capacitor With capacitor
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Meratakan litar gelombang penuh Smoothing the full-wave circuit
No capacitor With capacitor
10. REPUTAN RADIOAKTIF (RADIOACTIVE DECAY)
1. Ciri-ciri reputan radioaktif (Characteristics of radioactive decay):
- berlaku rawak & spontan (random & spontaneous process)
- membebaskan sinaran radioaktif (release radioactive radiations)
2. 3 jenis reputan (3 types of decay):
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a. Reputan alfa / alpha decay
- membebaskan zarah alfa (nukleus helium) (α) release alpha particle (helium nucleus) (α)
- contoh/ example:
210 84 Po → 206 82 Pb + 4 2 He
b. Reputan beta/ beta decay
- membebaskan zarah beta (elektron gerak pantas) (β) release beta particle (fast-moving electron) (β)
contoh/ example:
24 11 Na → 24 12 Mg + 0 -1 e
c. Reputan gama/ gamma decay
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- membebaskan sinar gama berfrekuensi tinggi (γ) Release high frequency gamma ray (γ)
Contoh/ example:
60 27 Co → 60 27 Co + γ
3. Graf menunjukkan pereputan/ Graph showing decaying process
Maklumat/ Info:
- Nukleus radon (Rn) mereput menjadi plumbum (Pb)
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Nucleus of radon (Rn) decays into lead (Pb)
- 4 pereputan alfa & 4 pereputan beta telah berlaku 4 alpha decays & 4 beta decays have occurred
- Proses-proses ini berlaku secara rawak & spontaneous This processes are random & spontaneous
- Ini berlaku sehingga menjadi plumbum dgn nukleus stabil These occur until lead is formed with stable nucleus
11. KESAN FOTOELEKTRIK (PHOTOELECTRIC EFFECT)
1. Definisi = Fenomena permukaan logam (katod) membebaskan elektron (fotoelektron) apabila disinari cahaya dgn frekuensi tertentu Definition = phenomenon of metal surface (cathode) releasing electron (photoelectron) when illuminated with light with certain frequency
2. Empat ciri-ciri kesan fotoelektrik (Four characteristics of photoelectric effect)
a. 4 syarat perlu dipenuhi sebelum fotoelektron dibebaskan - fungsi kerja, voltan pengaktifan, frekuensi ambang (paling minimum), &
panjang gelombang maksimum)
(Terms to release the photoelectron - work function, activation
voltage, threshold (minimum) frequency, & maximum wavelength)
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b. Fotoelektron dibebaskan serta-merta, berbanding dlm pancaran termion dimana elektron mengambil masa utk dibebaskan
(Immediate release of photoelectron, compared to thermionic emission in cathode ray which takes its sweet time to do so)
c. Frekuensi cahaya mempengaruhi tenaga kinetik maksimum fotoelektron
(Frequency of light affects the photoelectron's maximum kinetic
energy)
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d. Keamatan cahaya mempengaruhi kadar pembebasan fotoelektron, tetapi tidak mempengaruhi tenaga kinetik maksimum fotoelektron).
(Light intensity affects the rate of photoelectron being released, but it does not affect the photoelectron's maximum kinetic energy)
3. 2 siri eksperimen melibatkan kesan fotoelektrik (2 series of
experiments involving photoelectric effect)
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EXP 1 Mengkaji hubungan antara voltan & arus
(Investigate relationship between voltage & current)
EXP 2 Mengkaji hubungan antara panjang gelombang & voltan pengaktifan
(Investigate relationship between wavelength & activation voltage)
EXP 1:
Mengkaji hubungan antara voltan & arus
(Investigate relationship between voltage & current)
Keputusan/ result:
Arus meningkat secara linear dgn voltan (Current increases linearly with the voltage)
Drpd pintasan-V:
kita boleh cari voltan pengaktifan, Va (voltan minimum diperlukan utk kesan fotoelektrik berlaku) From V-intercept:
MV : Selaraskan potensiometer utk mengubah nilai voltan
(Adjust potentiometer to change the
voltage)
RV : Perhatikan
bacaan miliammeter utk nilai arus
(Observe miliammeter
reading for current value)
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we can find activation voltage, Va (minimum voltage needed for photoelectric effect to happen)
EXP 2:
Mengkaji hubungan antara panjang gelombang & voltan pengaktifan
(Investigate relationship between wavelength & activation voltage)
Keputusan/ result:
Voltan pengaktifan meningkat secara linear dgn 1/panjang gelombang Activation voltage increases linearly with 1/wavelength)
MV: Ulang eksperimen tadi dgn warna LED
berbeza (panjang gelombang berbeza)
(Repeat previous experiment using different
LED colour (different wave length)
RV: Berdasarkan graf V lawan I yg dibina, cari voltan pengaktifan Based on V-I graph you built, find activation voltage
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