Rabu, 13 Februari 2013

CERPEN ( CANTIKA SI JELEK )


“Cantika Si Jelek”
                Dengan wajah lesu, lunglai dan pipi yang memerah seperti tomat cantika berjalan menuju kamarnya, dan sesampainya dikamar cantika melempar tasnya ke kasur dan menghampiri cermin yang ada disudut kamarnya. “huffff...... kayaknya mama sama papa salah kasih nama aku deh, iya nama aku cantika yang berarti cantik sedangkan aku udah gendut, jerawatan dan kulit hitam lagi, gak ada cantik-cantiknya deh” (kata cantika sambil melihat-lihat dirinya dari atas kebawah kiri kekanan di cermin). Lalu cantikapun merebahkan badannya dikasur sambil meratapi nasibnya dan tidur.

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            Saat disekolah teman-teman cantika selalu memanggilnya dengan sebutan KD ( eitsss..... bukan krisdayanti loh tapi kudanil) huh...huhu.... kuping cantika selalu panas dengar teman-temannya memanggilnya dengan sebutan kudanil, dia sebel, jengkel, dan kesel banget sama teman-temannya yang hobby banget mengejeknya. Disekolah cantika selalu merasa minder sama teman-temannya yang berbeda 360 derajat dari dia, yang bagaikan bumi dan langit sama dia yaitu cewek-cewek modis dan cantik seantera sekolah, cantika selalu gak pede dia selalu menyendiri dan melakukan hobbynya melamun dikelas “Andai aku bisa cantik seperti artis-artis dikorea, andai aku bisa sexy seperti mereka wuidihhh pasti senang banget ya”, ucap cantika yang menghayal sambil senyum-senyum seperti orang abis menang undian berhadiah dan saat bel masuk berbunyi cantika pun mengentikan khayalannya yang konyol dan gak akan pernah menjadi kenyataan itu.

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            Sepulang sekolah cantika melanjutkan khayalannya yang terganggu oleh bel sekolah tadi dan tiba-tiba mamanya datang dan menyapanya “kamu kenapa sayang dari tadi mama panggilin gak nyaut-nyaut” ( tanya mama cantika dengan penuh kelembutan pada anak semata wayangnya itu ). “ ma, kenapa cantika ini jelek ya ma, cantika gak cantik seperti teman-teman cantika, apa ini kutukan ya ma ! “ (cantika balik nanya sama mamanya). Mama cantika pun menasehati anaknya bahwa itu sudah takdir, jadi cantika harus bersyukur dan menerima dirinya apa adanya, karna kesempurnaan itu hanya milik Allah, dan seharunya cantika harus merasa lebih bersyukur karena diluar sana banyak orang-orang yang tidak mempunyai tubuh sempurna alias cacat. Tapi cantika masih saja menganggap dirinya orang yang paling jelek sejagat raya, seantera dunia, cantikapun keluar rumah dan  mengabaikan perkataan mamanya dia selalu menggap kejelekannya sebagai kutukan.

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            Cantika yang meratapi nasibnya berjalan tak menentu, berjalan terus dengan wajah yang  suntuk dan badmood dan saat dijalan cantika melihat anak kecil yang sedang menyebrang jalan dan ada mobil yang ingin menabrak si anak tersebut. Cantika yang melihatnya langsung menolong sianak tersebut “aduhh adek jalannya hati-hati dong, liat kiri kanan biar gak ketabrak” (kata cantika pada anak tersebut), “maaf kak saya buta, saya gak bisa liat kalo ada mobil lewat tadi” (jawab si anak dengan wajah polosnya). Cantikan yang diam-diam memperhatikan anak itu sontak terkejut dan diam ketika anak itu meraba-rabanya  sambil mengucapkan terima kasih. Cantikapun terus melanjutkan perjalannya yang tak tau kemana tujuannya dan tak disadari cantika melihat anak-anak yang sedang ngamen dan ngemis dijalan, hatinya menjadi tesentuh melihat anak-anek tersebut, dan tak jauh dari sana cantika melihat sebuah panti asuhan, cantika melihat anak-anak kecil dan bahkan masih balita sudah dititipi dipanti asuhan, tapi mereka bahagia dan menikmati hidup dengan senang dan suka cita padahal mereka tau kalau mereka gak punya orang tua, cantika pun menjadi makin tersentuh yang sedari tadi melihat anak-anak tersebut cantika mulai sadar bahwa tidak ada orang yang senmpurna dan dia menyadari bahwa masih banyak orang yang lebih menderita dari dia. Cantika yang gak tau mau kemana lagi akhirnya pulang dan sesampainya dirumah dia langsung mencari mamanya “mamaaa.... maafin cantika tadi ya, cantika sayang mama, cantika juga bangga punya supermom seperti mama, cantika juga sadar kalau kesempurnaan itu hanya milik Allah” (ucap cantika sambil memeluk mamanya dengan manja).

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            Besoknya disekolah cantika yang biasanya minder dan selalu takut diejekin teman-temannya kini menjadi lebih percaya diri, dia sudah sadar bahwa sikapnya selama ini itu yang membuat teman-temannya semakin senang mengejeknya, dan seperti biasa sesampainya dikelas cantika selalu dipanggil kudanil sama teman-temannya, tapi kali ini cantika menanggapinya dengan santai dan senyum semringah. Dan salah satu teman cantika pun mendekatinya “eh kudanil kok dari tadi dipanggilin gak dengar sih” ( ujar salah satu teman cantika ). “oh kalian manggil aku ya ? sorry aku gak tau habinya gak ada yang manggil cantika dari tadi, nama aku itu cantika ca-n-ti-ka bukan kudanil lagian nama orang kok diganti-ganti emang aku sudah potong kambing apa” (jawab cantika dengan santainya sambil tersenyum lima jari). Teman-teman sekelasnyapun heran dan saling pandangan satu sama lain. Cantika yang melihat expresi teman-temannya itu langsung senyum-senyum sendiri dan berkata BE YOUR SELF itu emang menyenangkan dari pada ingin selalu menjadi orang lain.

THE END

                                                                                                           Created by Novia Sari Afrijhon :)

Rabu, 26 Desember 2012

FINAL EXAM


1.      Kinetic Energy
Kinetic energy is energy that a motion object. Energy that objects similar to the work done by the force acting on the object to change the object from being still to a state of motion.
The kinetic energy there are 2, that are :
- Translational kinetic energy is the energy owned by objects that motion on a straight track
- Kinetic rotational energy is the energy owned by objects that do rotational motion.

          Okay I observed a door in my house, when we pushed open the door, the door also rotates or rotating on an axis. The hinge that connects the door to the wall serves as the axis of rotation. and when the door is rotates door edges motion faster or more speed. Instead part door near the hinges to motion more slowly or less velocity. So when an object rotates, the velocity (v) of each particle is different, depending on the distance from the axis of rotation. Because each particle has a mass (m) and velocity (v) then we can say that when a rigid rotates, the particles that make up all matter has a kinetic energy of translational kinetic energy, and the total kinetic energy of all the particles that make the same rigid kinetic energy of rigid. Mathematically it can be written :



And in my observation happens rotational kinetic energy. Unit of kinetic energy is the joule, the same as other forms of energy. The kinetic energy is usually dependent on the mass and velocity, but the rotational kinetic energy is dependent by the moment of inertia and angular velocity.



Problem solving :
 
The door rotates on its axis with a moment of inertia of 0.15 Nm and angular velocity of 10 rad / s. How Ek rotation ?
Known : I    =   0,15 Nm
             ω  = 10 rad/s
Ek = ½ I ω
     = ½ . 0,15 Nm . 10 rad/s
     = 0,75 Joule

so we can assume that if the moment of inertia of a rotating door of 0.15 Nm and angular velocity 10 rad / s the kinetic energy of rotation is 0.75 joule.

 
2.      Frictional force

Friction is the force directed against the direction of motion of objects or inclination objects will motion. Frictional forces appear when two objects come into contact. Large friction force depends on the rough and smooth surfaces friction against each other. Rough surfaces will cause friction force is relatively larger than a smoother surface, the friction force is dependent object weight but not object surface area is dependent.

static friction force
           Static friction is friction between two solid objects that are not moving relative to each other. As an example, static friction can prevent object sliding down the incline. The coefficient of static friction is generally denoted by μs, and generally larger than the coefficient of kinetic friction.
Static friction resulting from a force that is applied just before the object is moving. The maximum frictional force between two surfaces before the movement is the result of the static friction coefficient multiplied by the normal force Fn f = μs. When no movement occurs, frictional forces can have a value of zero to the maximum friction. Each style is smaller than the maximum friction force trying to move one of the objects will be countered by the force of friction is equal to the force but opposite direction. Any force larger than the maximum friction will cause the movement occurs. Once movement occurs, static friction force can no longer be used to describe the kinetics of object, making use of kinetic friction.

Kinetic friction force
          Kinetic friction (or dynamic) occurs when two objects move relative to each other and friction each other. The coefficient of kinetic friction is generally denoted by μk and generally always smaller than the static friction for the same materials

Types of friction

There are two kinds of friction between two solid objects together moving forwards, the static friction and kinetic friction, which differentiated between the touch points between the two surfaces that remain or are changing (shifting). For objects that can be rolled, there is also another type of friction is called rolling friction (rolling friction). For a rotating object perpendicular to the surface or air-spin, there is also friction spin (spin friction). Frictional forces between the solid and the fluid is called the Carioles force-Stokes or viscous force (viscous force).

Frictional force advantage and disadvantage

Examples of advantage friction force:
a. Footwear shoes and sandals made ​​of rubber and the like, and form is such that if used will resist use in   order not to slip.
b. Car tires, bicycle tires and motorcycle tires are made of rubber and form in design so that zoom in friction between the tire with road was also made rough.

Examples of disadvantage friction force:
a. Gir wheel and chain on the bike and a motorcycle or other parts that are friction can wear and damage. work reduce this friction can provide oil as a lubricant
b. In the car, motorcycle, or machines in the factory is always friction between the parts of the machine that quickly wear out or damaged. work reduce the this friction can provide oil as a lubricant.

purpose:
a. Determine the coefficient of static friction and kinetic coefficient of friction of the two surfaces
b. Determine the speed and acceleration of the motion on an inclined plane
-          The coefficient of static friction coefficient of friction between the two surfaces collide silent.
-          The coefficient of kinetic friction: the friction coefficient of the objects that collide in which objects move relative to one another.
The coefficient of friction arises because of the combination of two surface therefore the friction force vector is always painting on the surface of the meet.

Tools and materials:                                         
1. surfboard
2. block of wood
3. ruler measuring
4. stopwatch

Procedures:
*  Determine the coefficient of static friction
1. Put a block of wood on surfboard
2. Slowly lift surfboard until block reaches a position where the block will move right. Stop lifting and hold the surfboard in position.
3. Measure the price of x and h. Enter the data field
4. Repeat steps 1,2 and 3 with prices of different x
5. Calculate the coefficient of static friction

* Determine the coefficient of kinetic friction
1. Put a block of wood on surfboard
2. Slowly raise and stop the surfboard from sliding block current at the time and stop the stopwatch turn right when block reaches the end of the surfboard. Record the time in the field of data
3. Measure the distance x, h, and s in that position and record the data field
4. Repeat steps 1,2 and 3 with different price x
5. Calculate the coefficient of kinetic friction it


3.     Calculating Electrical of resistance circuit
In generally, circuits resistance classified into circuit of series resistance, parallel resistance, or a combination of both. To create a series or parallel resistance circuit a minimum of two resistance. Meanwhile, to make a circuit series-parallel combination of resistance required at least three resistance. The types of circuit resistance has its own advantages and disadvantages of each.

Series circuit
        The circuit is one of the series circuit are arranged on equal footing (series).  Two or more resistance are arranged in a sequence called the series resistance. Resistance in series to form an electrical circuit is not branched. current flowing at any point of the same magnitude. The purpose circuit series resistance to increase the value of electrical resistance and dividing the potential difference of the voltage source. The circuit resistance can be replaced with a series of resistance called substitute series resistance (Rs).




Parallel circuit
        Parallel The circuit is one electrical circuit arranged lined up (parallel). Two or more resistance are arranged side by side called parallel resistance. resistance are arranged parallel to form electrical circuits branched and have more than one lane of electric current. Arrangement of parallel resistance can be replaced with a resistance called substitute resistance parallel (Rp).



Series circuit - Parallel of Resistor (Mixed)
        circuit mix is a combination of resistor series circuit with resistor parallel circuit. mixed circuit is a circuit that is composed of a series circuit and parallel circuit in a single circuit for example, look at the picture.




Problem solving :
What is the total R value of a circuit mixed ((R1 + R2) / / R3) + R4 ?


Known :
R1 = 3 ohm
R2 = 3 ohm
R3 = 6 ohm
R4 = 7 ohm

Answer :

Rs   = R1 + R2
       = 3 ohm + 3 ohm
       = 6 ohm 
1/Rp    = 1/Rs + 1/R3
            =  1/6ohm  + 1/6ohm 
            =2/6 ohm         
 Rp      =  3 ohm
                       
 R total       = ((R1+R2)//R3) + R4               
                  = (Rs//R3) + R4                                             
                  = Rp + R4                                                      
                  =  3ohm + 7ohm                             
                  = 10 ohm                                                                
                                                                                                                                          
                                                                                                           
4. Sound as a wave
         The waves are part of the energy vibrations that propagate. Sound waves can not propagate in a vacuum because there is no in the room air particles in the air.

            Wave by the medium can be divided into 2 types:Mechanical waves in the wave propagation need a medium. Examples of mechanical waves are sound waves.
- Electromagnetic waves are waves that do not need the propagation medium. Examples of electromagnetic waves are light wave
 

Wave direction to knock divided into 2 types:
- Transverse waves are waves that knock the direction perpendicular to the direction of vibration. For example, light waves.
- Longitudinal waves are waves that knock the direction parallel to the direction of vibration. Longitudinal wave consists of density and
strain

The waves can be used in everyday life such as artificial satellites, solar cells, sonar, and oil and gas exploration.
sound is a mechanical wave that is longitudinal. According frequency sound waves are divided into 3 infrasonic, and ultrasonic audiosonic. The third sound is the result of the vibration of an object. Vibration sound sources surrounding air vibrate and propagate all directions as a longitudinal wave. Sound waves are collected by the outer ear and the eardrum vibrate further.
Wave
 type sound is just sound audio that can be captured by the human ear. Sound waves propagate in the form of density and strain so that the sound can travel through solids, liquids, and gases. Sound waves are very easy to experience diffraction. That is why we can hear the sound of a car engine before the bend in the road even though we have not seen the car because it was blocked by tall buildings alongside a bend.