UNIT 1: IDENTITI DIRI
Friday, July 19, 2013
Geografi ting.1 bab 9
Pergerakan Bumi
Pergerakan bumi terdiri daripada dua jenis pergerakan, iaitu:
- Putaran Bumi
- Peredaran Bumi
Rajah 1: Putaran dan peredaran Bumi. Bumi berputar di atas paksinya sambil beredar mengelilingi matahari
Info:
- Pergerakan bumi: Putaran bumi pada paksinya sambil beredar mengelilingi matahari mengikut orbit bumi.
- Putaran bumi: Pergerakan bumi dari barat ke timur.
- Peredaran bumi: Pergerakan bumi mengelilingi matahari mengikut orbitnya.
Putaran Bumi
- Bumi berputar pada paksi iaitu satu garis lurus rekaan yang menganjur dari kutub utara ke kutub selatan.
- Paksi condong 23 1/2 darjah pada satah tegak.
- Putaran bumi dari barat ke timur
- Menyebabkan matahari kelihatan terbit dari sebelah timur dan terbenam di sebelah barat.
- Satu putaran mengambil masa 24 jam.
Rajah 2: Kutub Utara dan Kutub Selatan
Kesan Putaran Bumi
1. Kejadian Siang dan Malam
- Semasa berputar, permukaan bumi yang menghadap matahari akan mengalami siang.
- Manakala permukaan yang terlindung daripada matahari akan mengalamai malam.
Rajah 3: Kejadian Siang dan Malam
2. Air Pasang Surut
- Kejadian air pasang surut ialah kejadian aras air tinggi dan arad air rendah di laut.
- Berlaku akibat tarikan graviti bulan dan matahari.
- Tarikan graviti bulan menarik air laut di permukaan bumi yang menghadap ke bulan dan menghasilkan air pasang.
- Air pasang dan surut berlaku dua kali dalam tempoh 24 jam.
- Terdapat dua jenis air pasang surut :
a) Pasang perbani
b) Pasang anak
- Tarikan graviti menjadi lebih kuat apabila bulan dan matahari bertindak bersama menghasilkan air pasang pada paras maksimum.
- Pasang perbani berlaku apabila bulan, matahari dan bumi berada dalam kedudukan lurus.
- Jika bulan, matahari dan bumi berada pada sudut tegak, maka terjadilah pasang anak.
Peredaran Bumi
- Bumi mengelilingi matahari pada orbitnya mengikut arah lawan jam.
- Satu peredaran bumi 365¼ hari atau setahun.
- Kesan peredaran bumi:
a) Pengiraan tahun dan tahun lompat.
b) Gerhana matahari
c) Gerhana bulan
d) Kejadian empat musim
Kesan Peredaran Bumi
1. Gerhana
- Gerhana merupakan keadaan yang berlaku apabila kedudukan bulan, matahari dan bumi berada dalam satah mendatar yang sama.
- Jika bumi berada di antara matahari dengan bulan, bayang bumi akan jatuh pada bulan. Maka terjadilah gerhana bulan.
- Jika bulan berada di antara matahari dengan bumi, bayang bulan akan jatuh pada permukaan bumi. Maka terjadilah gerhana matahari.
- Gerhana tidak berlaku kerap kerana jarang berlaku ketiga-tiga objek berada dalam kedudukan sebaris. Biasanya berlaku dua hingga emapt kali setahun.
a) Gerhana Bulan
- Bulan tidak mengeluarkan cahayanya sendiri.
- Bulan memperoleh cahaya daripada matahari.
- Apabila bumi berada antara matahari dengan bulan, cahaya matahari dihalang oleh bumi.
- Oleh itu bayang bumi akan jatuh pada permukaan bulan menyebabkan berlaku gerhana bulan.
Rajah 6: Fasa Gerhana Bulan
b) Gerhana Matahari
- Gerhana matahari berlaku apabila bulan berada di antara matahri dengan bumi
- Cahaya matahri terlindung oleh bulan dan bayang bulan akan jatuh pada permukaakaan bumi.
Rajah 8: Gerhana Matahari
2. Kejadian 4 Musim
- Kejadian emapt musim berlaku disebabkan oleh peredaran bumi mengelilingi matahari.
- Pergerakan bumi ini adalah mengikut lawan pusingan jam yang mengambil masa kira-kira 365¼ hari.
Rajah 9 : Kejadian Empat Musim
a) Ekuinoks Musim Bunga
- Matahari tengah hari tegak di Garisan Khatulistiwa
- Musim bunga di Hemisfera Utara
- Musim luruh di Hemisfera Selatan
- Siang dan malam sama panjang
b) Solstis Musim Panas
- Matahari tengah hari tegak di atas Garisan Sartan
- Musim panas di Hemisfera Utara
- Musim sejuk di Hemisfera Selatan
- Siang lebih panjang di Hemisfera Selatan
- Matahari tengah malam di Kutub Utara
c) Ekuinoks Musim Luruh
- Matahari tengah hari tegak di Garisan Khatulistiwa
- Musim luruh di Hemisfera Utara dan musim bunga di hemisfera Selatan
- Siang dan malam sama panjang di seluruh dunia
d) Solstis Musim Sejuk
- Matahari tengah hari tegak di Garisan Jadi
- Musim Sejuk di Hemisfera Utara dan musim panas di Hemisfera Selatan
- Siang lebih panjang di Hemisfera Selatan
- Matahari tengah malam di Kutub Selatan
Rajah 10: Jadual Rumusan Kejadian 4 Musim
Rumusan
- Sistem suria terdiri daripada matahari dan sembilan planet.
- Putaran bumi pada paksi menyebabkan siang malam serta air pasang surut.
- Peredaran bumi pada orbit menyebabkan kejadian 4 musim dan gerhana.
- Gerhana berlaku apabila bulan, matahari dan bumi berada pada kedudukan selari.
- Gerhana bulan berlaku apabili bumi berada antara matahri dengan bulan.
- Gerhana matahari berlaku apabila bulan berada antara matahri dengan bumi.
9.2 Cuaca Dan Iklim Malaysia
Negara
kita mengalami iklim khatulistiwa yang panas dan lembap sepanjang
tahun. Iklim ini dialami oleh kawasan yang terletak pada atau
berhampiran dengan Garisan Khatulistiwa. Terdapat empat ciri-ciri iklim
di Malaysia iaitu :
1. Iklim
- Malaysia mengalami iklim Khatulistiwa
- Panas dan lembap sepanjang tahun
- Siang dan malam hampir sama panjang setiap hari
2. Suhu
- Suhu yang tinggi sepanjang tahun
- Min suhu tahunan adalah kira-kira 27oC
- Julat suhu tahunan adalah kecil kira-kira 1oC hingga 3oC
3. Angin
- Dipengaruhi oleh sistem angin utama
- Angin Monsun Timur Laut
- Angin Monsun Barat Daya
- Angin Sumatera
- Sistem angin tempatan
- Bayu laut
- Bayu darat
4. Hujan
- Hujan lebat sepanjang tahun
- Jumlah hujan tahunan ialah kira-kira 2600mm
- Kebanyakannya hujan perolakan
- Hujan maksimum turun pada musim peralihan monsun di kebanyakan kawasan.
9.3 Faktor-faktor Yang Mempengaruhi Cuaca Dan Iklim Malaysia
1. Kedudukan
- Kedudukan Malaysia berhampiran Khatulistiwa menyebabkan suhunya tinggi
2. Ketinggian
- Ketinggian mempengaruhi suhu di sesuatu tempat. Contohnya
- Kuala Lumpur (39m) - Min suhu tahunan (26oC)
- Tanah Tinggi Cameron (1448m) - Min suhu tahunan (18oC)
- Setiap kenaikan 165m, suhu turun 1oC
- Semakin tinggi sesuatu tempat semakin rendah suhunya
3. Angin Monsun
- Angin monsun menyebabkan taburan hujan di Malaysia
- Taburan hujan:
- Kawasan paling lebat ialah Bukit Larut
- Kawasan sangat kering ialah Kuala Pilah
4. Kepulauan
- Kawasan yang berhampiran dengan laut mempunyai julat suhu yang lebih besar
- Kawasan pedalaman mempunyai julat suhu yang lebih kecil. Contoh:
- Kuala Pahang (6.4oC)
- Temerloh (9.4 oC)
Friday, July 12, 2013
MATHEMATICS
MATHEMATICS - FORM 1 |
LINES AND ANGLESANGLES A) Identifying an Angle angle is formed by two straigth lines that meet at a point called the vertex. For example : - In the figure above, (a) AOB is an angle. (b) OA and OB are called the arms of the angle. (c) O is the vertex, that is the point where the two arms meet. Worked Example 1 Mark the angle in each case. (a) (b) Solution (a) (b) B) Naming an angle An angle can be named by using one letter or three letters. For example :- Worked Example 2 C) Measuring Angles 1. Angles are measured in units called degrees ( 0 ). 2. To measure an angle, we can use an instru- ment called the protractor as shown below. 3. Note that if we read from left to right ( clockwise direction ), we use the inner scale. 4. To measure an angle less than 1800, <KLM, follow the steps below. Method 1 : Step 1 Place the protactor that its centre is on the vertex L. Adjust the protractor until its base line corresponds with the arm LM. Step 2 Read the value of <KLM using the inner scale. Therefore, <KLM = 300. Method 2 : Step 1 Place the protractor so that its centre is on the vertex L. Adjust the protractor until its base line corresronds with the arm LK. Step 2 Read the value of <KLM using the outer scale. Therefore, .KLM = 300 5. To measure an angle which is more than 1800, follow the steps below : To measure <STU Step 1 Produce the arm ST to V and measure <STV. <STV = 1800 Step 2 Place and adjust the protractor as shown to measure <VTU. Step 3 <STU = <STV + <VTU = 1800 + 200 = 2000 D) Drawing Angles Using a Protractor 1. We can also use a protractor to draw an angle. 2. To draw <RST =600, follow the steps below. Step 1 Draw an arm ST with S as the vertex. Step 2 Place the protractor so that its centre is on the vertex S and its base line is on ST. Step 3 Find 600 at the inner scale and mark it with a point. Call this point R. Step 4 Remove the protractor and draw a line to join R with S. Step 5 Mark and label <RST as 600. 3. To draw <KLM = 2400 ( more than 1800 ), follow the steps below. Step 1 Draw an arm KL with L as the vertex. Step 2 Place the protractor so that its centre is on the vertex L and its base line is on KL. Mark the point M at 600 on the outer scale. Step 3 Remove the protractor and join LM with a straight line. Step 4 Label <KLM as 2400. E) Identifying the Different Types of Angles The table below shows the different types of angles. Worked Example 3 Which of the following angles is acute, obtuse, reflex or right-angled? (a) 1650 (b) 900 (c) 2340 (d) 830 Solution (a) 1650 is an obtuse angle. (b) 900 is right angle. (c) 2340 is a reflex angle. (d) 830 is an acute angle. G) Determining the Sum of Angles on a Straight Line 1. Use a protractor to measure the angles on the straight line. Worked Example 4 Using a protractor, measure the angles on the straingh line KLM. Then, find the sum of the angles in each case. (a) (b) Solution (a) x = 1200 , y = 600 x + y = 1200 + 600 = 1800 (b) p = 400 , q = 900 , r = 500 p + q + r = 400 + 900 + 500 = 180 2. In general, the sum of the angles on a straight line is 1800. For example :- AOB is a straight line. x + y + z = 1800 H) Determining the Sum of Angles in One Whole Turn 1. A protractor is used to measure the angles at a point. Worked Example 5 Use a protractor to measure the angles in the figures. Then, find the sum of the angles in each case. (a) (b) Solution (a) x = 1100 , y = 2500 x + y = 1100 + 2500 = 3600 (b) p = 1300 , q = 600 , r = 700 , s = 1000 p + q + r + s = 1300 + 600 + 700 + 1000 = 3600 2. In general, the sum of the angles that formed one whole turn is 3600. For example :- a + b + c + d + e = 360 I) Calculating Angles involving One Whole Turn Worked Example 6 Without measuring, calculate the angles marked. (a) (b) Solution PARALLEL LINES AND PERPENDICULAR LINES A) Determining Parallel Lines 1. Parallel lines are lines that will not meet however far they are produced either way. 2. They are at the same distance apart from one other For example :- (a) KL is parallel to RS or KL//RS (b) AB//CD (c) EF//HG EH//FG 3. To determine wheter two given lines are parallel or not, follow the steps below. Step 1 Mark two points P and R on of two straight lines. The points should be as far apart as possible. Step 2 Using a protractor ora set aquare draw the two perpendicular lines PM and RN as shown. Step 3 Measure PM and RN. The given lines are parallel to each other if PM =RN. B) Drawing Parallel Lines There are three methods to draw parallel lines. Method 1 : Using a ruler (a) (b) Method 2 : Using a protractor (a) (b) Therefore, PM//RN Method 3 : Using a set square (a) To draw a straight line through the point P and parallel to the straight line XY. (b) (c) (d) C) Determining Perpendicular Lines 1. If two straight lines intersect at 90 , we say the two lines are perpendicular to each other. For example :- 3. We can use a protractor or a set square to determine wheter two straight lines are perpendicular to each other or not. For example :- (a) (b) D) Drawing Perpendicular Lines 1. To draw a line perpendicular ti PR from a point M on PR, follow the steps as shown below. Step 1 Step 2 Join MN. The straight line MN will be perpendicular to PR at M. 2. To draw a line perpendicular to PR from a point M outside PR, follow the steps below. Step 1 Step 2 INTERSECTING LINES AND THEIR PROPERTIES A) Identifying Intersecting Lines We say the two straight lines intersect if they meet ( or cut ) at a point. This point is known as the point of intersection. For example :- B) Identifying Complementary Angle and Supplementary Angles 1. We know that when two lines are perpendicular, the angle formed by them is a right angle or 90 . 2. Two angles which add up to 90 are called comple- mentary angles. Each is the complement of the other. For example :- 3. We know that the sum of the angles on a atraight line is 180. 4. Two angles which add up to 180 are called supplemen- tary angles. Each is the supplement of the other. For example :- C) Determining Complementary and Supplementary Angles Worked Example 7 Find the value of x in each of the following. (a) (b) Solution D) Identifying Adjacent Angles on a Straight Line 1. When two straight lines intersect, the sum of the adjacent angles on a straight line is 180 . For example :- The angles x and y which CE makes with the straight line ACB are called adjacect angles on a straight line. Therefore, x + y = 180 2. When two adjacent angles together make up 180, they are called supplementary angles. Worked Example 8 Identify the different pairs of adjucent angles in the following. (a) (b) Solution (a) To determine adjacent angles on a straight line, measure the angles marked. If the sum of the angles is 180 , then they are adjacent angles on a straight line. x = 60 , y = 120 x + y = 60 + 120 = 180 Therefore, x and y are adjacent angles on the straight line DEF. (b) a = 110 , b = 50 , c = 130 , d = 70 a + d = 110 + 70 = 180 Therefore, a and d are adjacent angles on the straight line PRT. b + c = 50 + 130 = 180 Therefore, b and c are adjacent angles on the straight line PRT. E) Identifying Vertically Opposite Angles When two straight lines intersect, either pair of opposite angles are called vertically opposite angles. For example :- Intersection of the straight lines KL and RS. a and c are vertically opposite angles. b and d are vertically opposite angles. F) Determining the Size of Vertically Opposite Angles If two straight lines intersect, the vertically opposite angles are equal. For example :- G) Finding the Values of Adjacent Angles on a Straight Line Worked Example 9 KLM is a straight line . Find x. Solution H) Problem Solving involving Angles formed by Intersecting Lines Worked Example 10 In the figure above, AB and CD are straight lines. Find the values of x and y. Solution |
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