Lensa tipis adalah lensa yang ketebalannya dapat diabaikan sehingga pengukuran jarak titik fokus dilakukan dari satu titik yakni pusat lensa.

Pemantulan Pada Cermin Cekung

Sinar istimewa pada cermin cekung:
1.	Sinar datang sejajar sumbu utama cermin akan dipantulkan melalui titik fokus F
2.	Sinar datang melalui titik fokus F akan dipantulkan sejajar sumbu utama
3.	Sinar datang melalui titik pusat kelengkungan cermin M akan dipantulkan kembali

Enter your email address:

Lex I: Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare.
Hukum I: Setiap benda akan mempertahankan keadaan diam atau bergerak lurus beraturan, kecuali ada gaya yang bekerja untuk mengubahnya.

Lex II: Mutationem motus proportionalem esse vi motrici impressae, et fieri secundum lineam rectam qua vis illa imprimitur.
Diterjemahkan dengan cukup tepat oleh Motte pada tahun 1729 menjadi:

Enter your email address:

Pengertian Kalimat Efektif
Kalimat efektif adalah kalimat yang mengungkapkan pikiran atau gagasan yang disampaikan sehingga dapat dipahami dan dimengerti oleh orang lain.

Kalimat efektif syarat-syarat sebagai berikut:
1.secara tepat mewakili pikiran pembicara atau penulisnya.
2.mengemukakan pemahaman yang sama tepatnya antara pikiran pendengar atau pembaca dengan yang dipikirkan pembaca atau penulisnya.

Ciri-Ciri Kalimat Efektif

1.Kesepadanan
Suatu kalimat efektif harus memenuhi ptic gramatikal yaitu ptic subjek (S), predikat (P), objek (O), keterangan (K). Di dalam kalimat efektif harus memiliki keseimbangan dalam pemakaian struktur bahasa.

Contoh:
Budi (S) pergi (P) ke kampus (KT).

Tidak Menjamakkan Subjek
Contoh:
Tomi pergi ke kampus, kemudian Tomi pergi ke perpustakaan (tidak efektif)
Tomi pergi ke kampus, kemudian ke perpustakaan (efektif)

Enter your email address:

a. Suhu
Enzim terdiri atas molekul-molekul protein. Oleh karena itu, enzim masih tetap mempuyai sifat protein yang kerjanyas dipengaruhi oleh suhu. Enzim dapat bekerja optimum pada kisaran suhu tertentu, yaitu sekitar suhu 400 C. Pada suhu 00 C, enzim tidak aktif. Jika suhunya dinaikkan, enzim akan mulai aktif. Jika suhunya dinaikkan lebih tinggi lagi sampai batas sekitar 40 – 500 C, enzim akan bekerja lebih aktif lagi. Namun, pemanasan lebih lanjut membuat enzim akan terurai atau terdenaturasi seperti halnya protein lainnya. Pada keadaan ini enzim tidak dapat bekerja.
b. Derajat Keasaman (pH)
Enzim bekerja pada pH tertentu, umumnya pada netral, kecuali beberapa jenis enjim yang bekerja pada suasana asam atau suasana basa. Jika enzim yang bekerja optimum pada suasana netral ditempatkan pada suasana basa ataupun asam, enzim tersebut tidak akan bekerja atau bahkan rusak. Begitu juga sebaliknya, jila suatu enzim bekerja optimal pada suasana basa atau asam tetapi ditempatkan pada keadaan asam atau bas, enzimtersebut akan rusak.

Enter your email address:

Gowa is one of the district in South Sulawesi province. Gowa regency mostly hillyplateau. One of the districts that form the highlands of the district Tinggimoncong. District of Tinggimoncong are on the slope of 40 degrees. This district has a varied landscapes such as mountains, waterfalls, and others.

Bawakaraeng mountain is one of the existing landscape in the district Tinggimoncong. The distance is only 75 km from the city of Makassar. A high mountain about 2705meters above sea level is also a climbing arena. Broad peak of approximately 100 m2and in the east of this mountain clouds look thick and silent clot.

In addition to mount Bawakaraeng, one of  the attractive landscape in the district Tinggimoncong is Takapala waterfall. This waterfall is located approximately 5 Km, from the city center Malino Gowa regency, indeed be one of the main goals for theirenchanting beauty of nature seekers.This waterfall has a height of approximately 55 meters. 

Enter your email address:

1. Problem
Global warming is affecting many parts of the world. Global warming makes the sea rise, and when the sea rises, the water covers many low land islands. This is a big problem for many of the plants, animals, and people on islands. The water covers the plants and causes some of them to die. When they die, the animals lose a source of food, along with their habitat. Although animals have a better ability to adapt to what happens than plants do, they may die also. When the plants and animals die, people lose two sources of food, plant food and animal food. They may also lose their homes. As a result, they would also have to leave the area or die. This would be called a break in the food chain, or a chain reaction, one thing happening that leads to another and so on.

The oceans are affected by global warming in other ways, as well. Many things that are happening to the ocean are linked to global warming. One thing that is happening is warm water, caused from global warming, is harming and killing algae in the ocean.

Global warming is doing many things to people as well as animals and plants. It is killing algae, but it is also destroying many huge forests. The pollution that causes global warming is linked to acid rain. Acid rain gradually destroys almost everything it touches. Global warming is also causing many more fires that wipe out whole forests. This happens because global warming can make the earth very hot. In forests, some plants and trees leaves can be so dry that they catch on fire.

2. Cause
Many things cause global warming. One thing that causes global warming is electrical pollution. Electricity causes pollution in many ways, some worse than others. In most cases, fossil fuels are burned to create electricity. Fossil fuels are made of dead plants and animals. Some examples of fossil fuels are oil and petroleum. Many pollutants (chemicals that pollute the air, water, and land) are sent into the air when fossil fuels are burned. Some of these chemicals are called greenhouse gasses.

We use these sources of energy much more than the sources that give off less pollution. Petroleum, one of the sources of energy, is used a lot. It is used for transportation, making electricity, and making many other things. Although this source of energy gives off a lot of pollution, it is used for 38% of the ’ energy.

One of the examples of using energy and polluting the air is using an air conditioner.

When you do these things, you are causing more greenhouse gasses to be sent into the air. Greenhouse gasses are sent into the air because creating the electricity you use to do these things causes pollution. If you think of how many times a day you do these things, it’s a lot. You even have to add in how many other people do these things! That turns out to be a lot of pollutants going into the air a day because of people like us using electricity. The least amount of electricity you use, the better.

When we throw our garbage away, the garbage goes to landfills. Landfills are those big hills that you go by on an expressway that stink. They are full of garbage. The garbage is then sometimes burned. This sends an enormous amount of greenhouse gasses into the air and makes global warming worse.
Another thing that makes global warming worse is when people cut down trees. Trees and other plants collect carbon dioxide (CO2), which is a greenhouse gas

 3. Solution

As an individual, we can do many things to try to stop global warming. One thing we can do is carpooling. Carpooling is driving with someone to a place that you are both going to. This minimizes the amount of greenhouse gases put into the air by a car.

Another thing that we can do is being more careful about leaving things turned on like the television, computer, and the lights. A lot of people are taking time away from the television, and instead, they are spending more time outdoors. This helps our planet out a lot. Now, more people are even riding busses, walking to school, and riding their bikes to lower the amount of greenhouse gases in the air. Planting trees and recycling also helps. If you recycle, less trash goes to the dump, and less trash gets burned. As a result, there are fewer greenhouse gasses in our atmosphere.

Watch what you buy. Many things, such as hairspray and deodorant, now are made to have less of an impact on the atmosphere. Less greenhouse gasses will rise into the air, and global warming will slow down.

Enter your email address:

1. Conduction

Conduction is heat transfer  from metal (solid) that is not involving the transferred of the metal particles. For example, if you heat metal end, a few moments later the other end will be heated as well. It suggests that there is a heat transfer in metal. The heat is propagating from the high to low temperature ends. In other words, the heat transfer could only take places when there is a difference in temperature. If there isn’t, there would never be any heat transfer.

If it is heated, the kinetic energy of a substance’s particles is likely to increase. Keep in mind, all substance particles are vibrating. Since the kinetic energy increase, the particles influence the vibration of the neighboring around it. As the result, the particle vibration is increasing as well.  Then, the neighboring particles influence the next neighboring particle’s vibration. In this case, the substance particles are not migrating. It is the substance particle’s kinetic energy that is migrating . The amount of the particle’s kinetic energy is proportional to its temperature.

Based on the conductivity, substance could be divided into conductor and isolator. Conductor is a substance that can transmit heat easily, while isolator is the one that is hard to transmit heat.

2. Convection

Convection is a heat transfer that emerges due to the presence of the intermediate substance’s particle flow. In this, the heat is flowing with the particle flow. Heat transfer  in convection occurs in fluids, in example water and air. The water or air flow take place in two ways, those are naturally flowing and forced to flow. Therefore, heat transfer in convection could be divided into two, namely natural and forced convections.

a. Water Flow Vertically

The heated water will decrease in its mass density so that the weight decreases as well. As the result, the water moves upwards and its position is occupied by the water with greater mass density (cold water). During the heating, it will proceed continuously so that the vertical water flow would occur. That water flow that causes the heat to be spread to all parts of the water.

b. The Occurrence of Land and Sea Winds

At noon, the air temperature in land is higher than in the sea. The air in land with mass density of which is lower will raise and its place will be occupied by the cooler air. Therefore, the air flow occurs from the sea to the land referred as sea wind. Conversely, at night, the air temperature in land is lower than in the sea. This is due to the land can get cooler faster at night. As the result, there air flows from the land to the sea referred as land wind. During the shift of land and sea wind, we feel that there is almost no wind in the beach. When and why does it happen?

The example of convection discussed above is the natural one. The example of forced convection are, among others, the raise of water for being pumped with water pump and the entrance of water into the tire using a pump.

3. Radiation

There is a vacuum between the earth and sun. Heat can transfer through heat gh a vacuum. It is proved with the ability of the sun’s rays to achieve the earth. Heat transfer through a vacuum is done through radiation. In this case, the heat is radiated in the form of electromagnetic wave. Thus, electromagnetic wave propagates through a vacuum.

Every hot object radiates its heat in the form of electromagnetic wave. The radiated electromagnetic wave has certain wave length and frequency, depending on the temperature. If it reaches an object, electromagnetic wave undergoes three treatment possibilities; those are absorbed, reflected, or partly absorbed and partly reflected. However, if it reaches an object, generally, electromagnetic wave will be absorbed partly and the other part will reflected. The electromagnetic will be absorbed entirely if it reaches black objects and will be reflected entirely if it reaches shiny objects.

Enter your email address: