SUN

The sun is the center of the solar system. The sun is the largest object in solar system. It is diameter ia approximately 1,4 million kilometer it consists of hydrogent and helium. The sun is 333.000 times as massive as t

workshop

physics lessons for elementary schools, middle schools, high schools

Global Warming

Some plants are often grown in a glasshouse (greenhouse)What is advantage of a greehouse ?

extreme weather in Indonesia

frequent extreme weather in Indonesia, according to climatology meteorology and geophysics, extreme weather

greetings in Happy New Year 2012

Fisika Education : Teaching materials, practice questions and articles Physics for elementary, junior high school, vocational school

Thursday, January 26, 2012

Law of Love Monkey


Now let us study the Coulomb's law with the love parable teenagers (ABG), we call this law Law of Love Monkey let me not scary anymore with the physics lesson, or let me not boring anymore. But this is actually a method that does not theorize, but proven to be remembered forever by my students in high school.


Suppose that:
A is a high school kid, girl, gorgeous, rich, humorous, outgoing, caring, etc..
B is a high school kid, girl, gorgeous, smart, sociable, attentive, helpful if you see his friend in trouble.
C is a high school kid, male, handsome, often oversleep klo school, lazy, idol girls in high school because good music playing.



One day C invented by A, then there was an intimate love relationship romance. The C into the spirit entered his school, which usually come at 8 am, now five in the morning was perched at the school .... Hahaha! The power of love C of A is very large because in addition to falling within the scope of the SMA, A is also beautiful, humorous, wealthy, and attention at all.
One day their love story known to the parents of A, A worried parent learning activity is interrupted, so he moved his school to another school. Because the distance between school C with school A not so distant and so strong his love, now C back to its original habit, always late and lazy, but he was more active presence in the school veranda A.
A romantic relationship with C is found again by the parents of A, and the parents decided to send their A A overseas. Meranalah then the C, behavior begun to be lazy, now with a further distance away.
Looking at C is always moody, B feels pity, he approached, he advise, "be patient, when it certainly met her match again" he said. Attention B to C is so sincere and felt very encouraging for C. Begin arise affection for B, and C started working again to school, learning spirit re-emerged. Because of the distance A to C is very far away, love C of A begins to wear off. Moreover, there is now concern that were located very close to B to C. C then decided to establish in love with B. Shoots be loved side dish arrived, finally going with B. C
Well, if we suppose that A and B is a negative charge, C positive charge. According to Coulomb's Law states that "style attraction / repulsion between two charges declined proportional to the charge itself and berbading kuwadrat inversely with the distance between the two charges are" (Note: If the two charges were different types of attractive forces will occur, if the two charges together kind then there is a repulsive force declined).
So A and C will have the attractive forces (power of love) is very strong when the distance is relatively close, while the distance in the gravity pull away (ideal strength) will be weakened. When A and B away closer to C then the attractive forces between B and C will be stronger than attractive forces between A and C.
Mathematically formulated Coulomb's Law:

F = k (q1. Q2) / r ^ 2

q1 & q2 = charge,
r = distance between two charges,
k = dielectric constant, and
F = the Coulomb

Monday, January 23, 2012

The most bizarre planet

Many extrasolar planets have been found and diverse character. Some of them have peculiarities, such as orbiting two suns. Astronomers had studied the planet 55 Cancri e. The planet is orbiting a star 40 light years away from Earth, and was discovered in 2004. This is the most bizarre planet.

Research over the past few years revealed that 55 Cancri e entered the category of super-earth, mass 99 times Earth's. Observations of this planet do when planets transit in front of the star. Known, 55 Cancri e stopover in advance its star every 18 hours. So far, astronomers suspect that the condition of 55 Cancri e is very hot and cruel. This is because the distance of the planet and the star is very close, 26 times closer distance of the Sun-Mercury.

However, recent research reveals that 55 Cancri e was as alleged. Despite the close distance of the planet and its star, the planet has a liquid, including water. Liquid on the planet was not as envisaged, instead of the ocean as on Earth. The liquid contained inside, and seeps out through the rocks.

The existence of this fluid strange because this planet's surface temperature reaches 1,000 degrees Celsius. According to astronomers, the condition is possible because each fluid is in the super-critical conditions, the temperature is more than the boiling point (100 degrees for water), but remain in liquid form. As a result of water seepage into the surface of the planet, the planet's atmosphere becomes very hot and steamy. And, it can be detected from a distance of 40 light years.

The research was carried out by Brice-Olivier Demory from the Massachusets Institute of Technology and published in Astronomy and Astrophysics.
sains.kompas.com
2012

Year of the Dragon on Water

Year of the Dragon Water in the calendar year China will replace the Rabbit. Dragon is one of the strongest animal figures in the traditional Chinese calendar system, which has a specific form of drastic change, which could have occurred after the date of January 23, 2012 up to one year to the next lunar calendar.

Many young couples have a desire to have children or more children who were zodiac dragon. Especially couples who had zodiac rats, monkeys, and chickens, are known to have a match with zodiac dragon. Suitability of children with parents in the family is believed to bring good luck.

Feng shui, Mauro Rahardjo, who met in Surabaya, East Java, last week, telling, Water Dragon year will be greatly influenced by cycles of planet Jupiter. "This year is one of the strongest cycle of Jupiter which rotates about the Sun once every 12 years. The cycle of the Earth around the Sun in one year, "he said.

Mauro, who is also founder of the Feng Shui Society Indonesia, explained, 12 the position of Jupiter relative to Earth that is known as the zodiac (Chinese horoscope). The position of Jupiter is very influential on energy chi (Mandarin: qi) in the Earth's surface, not unlike the Moon affects the circulation of natural conditions such as tidal water on Earth. This is not superstition and Meteorological Laboratory has been investigated in the United States. Science of feng shui has long been observed and translate the science of Flying Stars (Fei Xing).

The resulting movement of chi energy spread across nine sectors Jupiter is depicted in a plot of 3 x 3 in accordance with the direction of the wind and a central point. Number 2 represented the north, northeast of number 9, number 4 east, southeast number 5, number 1 south, southwest of number 3, number 8 west, northwest of the number 7, and the central point number 6.

According to Mauro, how to interpret simple, that is like owning a home or office, can be seen whether the positive energy received in accordance with the calculation of nine points in the direction of the wind in the calculation of the Water Dragon year will bring good luck.

"Conversely, if that comes is a number or direction of the wind that carries negative energy, will affect the barriers and obstacles. However, something negative can be handled by not triggering the potential evils manifest into disrepute, "said Mauro.

Positive energy in 2012 will mainly be felt in the west, represented by figure 8 (a white star or Ba Bai). If the door of the house facing west or have a bedroom in the west, this success can also be felt by residents of the houses and the position of the entrance to the bedroom in that direction.

However, this also depends on the question whether being able to use the opportunities available or not. If you can not take advantage of this opportunity, it means losing a good opportunity.

The second sector of the energy gain is a good star southward to the arrival of white star-1 (Yi Bai). This energy brings fragrant name and fame, as well as the success in academics and professionals gain a good momentum.

4-star (Si Lu) which is an academic star and romance stars will occupy the east direction of the wind. This is extremely useful for those who work in academic and professional fields, as well as for those who do not get a mate, there is a good opportunity to get a girlfriend this year.

Other sectors are lucky the northeast. In this coming-9 purple star (Qiu Zi), who obtain health care, more extensive social networks, and joy in all aspects of life. If the door facing northeast, residents may be able to celebrate a feast of joy, among other things, a successful business, school, or there is a chance to celebrate a wedding.

In addition to the above positive energy, a number of other existing wind direction that tends to bring negative energy to the house or door facing that direction, such as the southeast, south, southwest, and northwest. However, Mauro warned not to get discouraged because it can be activated by the positive energy objects: vibrating, life (aquarium), reads, and luminous.

He reminded, in 2012 there will be taboos or restrictions to which a sector within buildings is prohibited to crowded, demolished, excavated and renovated. First, the negative energy that comes too strong is not good for disturbed with respect to the arrival of Tai Shui, the Year of the Dragon, which is located in the southeast (between 112.5 o-127, 5o). In this sector there should be no excavation of land or building renovations.

There is a good time working or sleeping bed is not in the direction of Tai Shui this. Similarly, the affected sectors of Wu Wang (5-yellow) in the southeastern and southern sector in 2012 exposed Samsart ("triple murder").

Time of birth

Separately, feng shui, Jennie Kumala Dewi, provide additional information about the meaning of luck in the year Water Dragon by considering the time element of a person's birth and various detailed calculations that can be attributed to the calculation of feng shui.

"This year should not be drastically changed professions. Should survive the competition that has been successfully passed in the year of Tiger and Rabbit. If you stick with what he pioneered, will enjoy the results of this year, "said Jennie, who is also an architect and presenter at a number of television stations.

Nationally, about Jennie, the condition of Indonesia will not be negative because it has a dragon zodiac zodiac compatibility with chicken which is the birth year of the Republic of Indonesia. Based on the calculation time of the birth, the nation Indonesia said to be spoiled and it can be proved by the abundant natural wealth.

In accordance with the nature of the dragon full of surprises, this year's estimated national figures emerged from the figure that is not favored, either from the young and old alike. Similarly in the world of celebrity, a number of old people will go back up and flying in the national level.

A number of professions that have a match with the Water Dragon year, said Jennie again, among which is the art of fashion, creative arts, design, and work associated with metals and machinery, including computers. This phenomenon happens like 12 years ago when the crash said to occur on computer systems (Y2K).

A number of professions with the element of fire and water will experience very severe competition is the banking sector, marketing, and world stocks. Similarly, businesses related to the circulation of goods, such as transportation.

All the calculations were based on feng shui and the computation time of birth (weton) which certainly can be tricked by hard work and careful.

Gong Xi Fa Cai, Happy and Prosperous Year of the Dragon on Water!
sains.kompas.com

Tuesday, January 17, 2012

Phobos Grunt .

Phobos Grunt fell Monday, January 16, 2012


JAKARTA, KOMPAS.com - Finally, the Russian spacecraft that failed in its mission to Phobos, Phobos-Grunt, declared to have fallen.

Deputy Science, Assessment, and Aerospace Information Institute of Aeronautics and Space Agency (Lapan), Prof. Dr. Thomas Djamaluddin, Monday (16/01/2012) says, "The last report of USSTRATCOM (U.S. Strategic Command), said the last radar data recorded at 23:36 pm and is based on recent data that Phobos-Grunt fall between the hours of 23:59 to 1:47 pm Monday night and early on January 16, 2012.

Meanwhile, astronomers Ma'rufin Sudibyo, Roscosmos quoted saying that the Phobos-Grunt crashed at 0:45 pm. Exact time of the fall of Phobos-Grunt is not yet certain.

Before the fall, Phobos-Grunt was through the territories of Central Asia, Western Pacific and South Pacific. This spacecraft also had to pass through Indonesia last night, the Halmahera region, Irian, the western side of Borneo and Nusa Tenggara.

Because time is uncertain, then the location too. Even so, it is believed that the Phobos-Grunt fell in the South Pacific region. Recent reports The Guardian and the RIA Novosti state that fell in Phobos-Grunt 1250 miles west of Wellington, off the coast of Chile, or in the waters east of Australia and New Zealand.

Thomas said, "To ensure this satellite which is difficult because it was falling off the radar observations. We must rely on witness statements in certain regions which saw the fall of the Phobos-Grunt."

While Ma'rufin said that Indonesia should be grateful because it was safe from the threat of falling satellites. "If only the Phobos-Grunt is still up there and pass two hours later, Indonesia spacecraft crossed this fail," he said.

Phobos-Grunt was launched on 9 November 2011 and then but then stalled in orbit because of navigation problems and run out of energy. The mission was supposed to land on Phobos to pick up rocks on the moon and Mars, but failed. It is estimated, there are 200 kg of Phobos-Grunt components that fell to Earth, torn between 20-30 pieces.

According to Thomas, Phobos-Grunt is not the first Russian spacecraft crashed. Lapan save 2 tube falling Russian rocket motors in 1981 and in Lampung. Meanwhile, the Mir space station also fell to Earth in the Pacific. The difference, Mir fell to the control.

sains.kompas.com

Monday, January 9, 2012

fisika gerakan Parabola

 meteri pelajaran gerakan parabola untuk fisika sma




Beberapa contoh syatem gerakan parabola download file Movement Parabola SMA

Wednesday, January 4, 2012

photo physics education

Collection of photographs of students studying information technology

Workshop physics education
sun physics education
logo fisikasbe physics education
teacher physics education
lab physics education
Bandung 14 indonesia 

students learn about information technology 2012

Monday, January 2, 2012

physics education Animals Voice

Animals Voice
(For elementary classes V and VI)

Younger siblings, sister had never made a sound that resembles a toy animals made from sardine cans. Holes in the can in one part and another part that is left alone, then perforated with a nail so that the string (yarn mattress) can sign extends downward. After that wet the thread with water, then pull the yarn and pull yarn emphasize at the index finger and thumb to pull the thread between a faltering, well that's when the sound may be withdrawn. His voice is funny and weird, could resemble the crowing cock, the sound of geckos or other sounds depending on how your fingers pull the thread that extends it.

Well brothers and sisters, now let's make these toys while learning how where physics concepts that occur in tools.

As for the materials / tools that we will use is:
1. Plastic cups rather large
2. Yarn mattress 1 meter
3. Toothpick


How to make:
1. Punch a hole through glass with a toothpick.
2. Put mattresses yarn through the hole and let the hole stretches in plastic cups.
3. Tie a toothpick with a thread on the outside of the glass.
4. Dampen the yarn with enough water mattress.
5. Tap threads mattress with two fingers from his lips and then pull the plastic cups, set the pressure to get the desired sound.

Result: If the coherency will hear a good yarn-like animal sounds (crowing sound
chicken, gecko voices, etc.)

Explanation:
At the time of yarn pulled mattresses, water mattresses serves to strengthen the yarn to yarn friction mattress seningga finger pull finger falters as a result of small jolt jolt-style press your fingers on the string. Jolt-jolt caused a vibration back and forth at the top of the glass that makes the air molecules inside the plastic cup also vibrate back and forth to the rhythm pull our fingers. While the glass behave like spiker (megaphone) that menjalarkan sound waves in one direction.
Well, younger brothers and sisters please give it a try, good luck! and happy new year 2012

Motion, Space and Time

Motion, Space and Time
( An afterthought )

Has become a common conception that the "motion" as could only be connected to the material. Though not demikia. In physics the ancient (traditional), the motion is divided into the motion of matter and wave motion. Waves can propagate without the need for propagation material. So the motion is essentially enegeri propagation.Energy is the ability to do business or motion.
In other words, Energy is the ability to move an object from rest to motion.
Einstein's Theory of Relativity has proved the equivalence of mass and engeri. The mass is energy, mass energy (E = mc2).
Nature is motion, the motion of air in the wind, waterfall motion, the motion of an amoeba-amoeba in water, and the motion of electrons around the protons, etc..
Degree heat of a gas is nothing but a macroscopic nature of the movement and collision ... trillion trillion trillion molecules of gas. Seen in the natural micro, from each molecule, the temperature has no meaning. There is only the energy of motion of the molecules. And this macro can be perceived by human senses and the senses of a measuring instrument and is called the temperature.

Electric current and the various symptoms of electronic circuits in none other than the movement of electrons through various media..
Is the propagation of water waves move energy through the nature of its medium-difat elestisitas, namely water.
Now we see the light, the light is the motion of propagation of electromagnetic energy through a medium or a vacuum.
Similarly, the sound, the sound is motion energy propagation through the vibration of air particles. When the vibration of the particles on the ear, will be recognized as sound.
In a variety of chemical reactions, actually happened motion of electrons transfer from one orbit to another orbit, so that the macro is identified by a variety of changes in chemical properties of various substances.
If we think something has the ability to influence others, it means we're thinking about engeri. If we think about something for a greater ability to be more sluggish, then something is more difficult to be moved by others. So because the mass equivalent to energy, then in a more general motion can be compared with the "energy" only. Since matter is energy itself, since the material is a subjective concept that has lost value keobyektifannya in Quantum Mechanics. If quantum mechanics is correct, konspesi of motion must be changed. We can not attribute a motion on something that does not exist objectively, ie the material.
So engeri is the ability to move a mass. Energy is the ability to move other energy, other energy is the ability to move other energy again, and so on. This will result in the definition of the chain without end, so this definition loses its meaning.
With a view definition, it can easily be proved that the force can dimaknakan as the energy change per unit distance traveled in space.
So it can be obtained three of the most fundamental elements in motion, namely: energy, space and time. Suppose first that these three elements axiomatic, can not be defined anymore. However, Einstein's theory of relativity back stating that space and time are not absolute, but relative. Can not be defined an absolute time and space. Space and time have a personal meaning, very personal.
A particle (I call them: energy!) Which moves relative to another particle (call me: other energy), each will have a life of its own!
So, if energy can be thought of as a being who has a certain degree of life and consciousness, then the space and time are subjective!
Furthermore they have no meaning without the motion of the object. Perhaps that is a basis of saying "Space and Time? Illusion, an illusion hanyala ". Space and Time lost its meaning in the absence of motion of the particle (I call: energy!).Furthermore, the ability to perform that movement of energy, and that is material.
Space and Time, is the illusion of motion.
As Sayyidina al-Husayn ibn Musa al-Bangili Ethiopia (ra) in mulyanya sermon: "Nothing else of this nature is motion and matter is the potential for movement".

In the emptiness of all
I found the space
and pulse nafaskupun realize the wheels of time
In the absence of space and time
I found the motion, the source of all images in Mayapada
Whether it's motion? I do not know
All I know is, if it was the only motion of Existing
then the motion will not move
There and Gone So what does this mean?
There and No is there any difference?
Behind There and Gone, I saw only one Itself,
My Lord, God Almighty in his solitude!
Sources: Dimitri Mahayana, collection of musings Physics, October 26, 1994

Resultan Vektor

Resultan Vektor
for high school physics ( Fisika sma smk )

When we train inside and outside of heavy rain, then we looked out the window. We see rain droplets fall sideways out there.
Why is that? This is caused by the existence of two movements moving in different directions.
1. The train moves horizontally with a speed νa.
2. Precipitation that falls perpendicular to the surface of the earth at νb.
If the two vectors that we put down at one point arrested then we will get the sum of the second vector is as below:


a = νa = speed of train
-a = - νa = velocity of the earth relative to the passenger
b = νb = velocity of the earth's rain
νc = c = speed of the rain relative to the passenger


From the description above it is clear that we see slanting rain outside the train isthe result of the resultant / sum of two vectors is the speed of the train velocity vectorand velocity vector rainwater  mutually perpendicular. The second resultant velocity vector is called the relative velocity of rain on us as a passenger train.

Note:
- The vector is a quantity that has a value and direction
- a = - νa, is actually the body's movement speed passenger who pushed back due to the speed of the train movement
for high school physics

Process of Sonic Boom

 Continued from physics lessons Doppler Effect 2
Process of Sonic Boom

F/A-18 Hornet flies at low heightof high  velocity. When is velocity reaches mach 1, a wall vapour around the airplane is formed.

The illustration above represents the sound wave fronts generated by an airplane moving with the same velocity as the sound wave.

The blue points in this illustration are the position of airplane when it emits the sound wave. As the speed of the source is the same as the velocity of the airplane, the sound wave of the point will accumulate and interfere in point. At this point many compressions will be found. As a result the air density at the point is very hight (as well its air pressure).
In order to move faster than the sound wave, the airplane should break throught the barrier of high air pressure.
Sound wave with the veri high amplitude will be heard as an explosion. Although it occurs verry short baut its vibration can break the window’s glass.
This explosion is called sonic boom.
Sometimes people misunderstand about this concept.
They assume that the explosion heard when supersonic airplane flies over them is because it is passing througt a barrier of high air pressure.


 File Process of Sonic Boom
physics education  physics lessons Doppler Effect 2 Process of Sonic Boom for high school

Doppler Effect 2

Continued from Doppler Effect 

If moves away from the source, then the wave received is less so that its frequency is lower. The formula for its frequency is :  

f’ = {(ν – νp)/ν}f

The conclusion of Doppler Effect :
a.       Source is in motion :
      Source approaches : use (-) sign (frequency is higher)
Source approaches : use (+) sign (frequency is lower)



b.      Observer is motion :
      Observer apppraeches : use (+) sign (frquency is higher)
Observer moves away : use (-) sign (frequency is lower)




moving sound sources in the circuit








shock wave frequency chart
ν = the sound speed
νs = the source relative speed to the observer
 f = the source frequency
f’ = the frequency heard by the observer            


continued >>> Doppler Effect
The next physics lesson on the process of Sonic Boom
Doppler Effect
Physics education for High School

Sun

The sun is the center of the solar system. The sun is the largest object in solar system.
It is diameter ia approximately 1,4 million kilometer it consists of hydrogent and helium.
The sun is 333.000 times as massive as the earth is.

The sun does not revolve around the Earth but vice-versa. Why does this happen ? Because the sun ‘s mass is so massive compared to the other object in the solar system. More than 99% of the mass of solar system is centered on sun, so that the celestial object revolve around the sun.There for it is reasonable that the Earth revovlve around the sun, not vice-versa If the rotationl objects system is seen from a reference at rest at large distance away., then the objects system will rotate to the center of gravity


A star is a self-luminous celestial body. The Sun is the closest to the Earth eith a distance of about 149.600.000 km

Why can a star make its own ligt ?  For file Download SUN <<<< Physics education for Junior High School SUN

Respiratory

 Sains Primary School Human Respirstory organ

 Human Respirstory organ,Nose
        Contaminating particles are trapped by the moisture of the mucus lining in the nasal cavity
        The respiratory organs consist of .In the Lung, bronchioles have many branches



















Rspiratory
Physics education primary school,

Mari membuat Suara Binatang dari Gelas

Mari membuat Suara Binatang dari Gelas Plastik Bekas
(Untuk SD kelas V dan VI)

Adik-adik, dulu kakak pernah membuat sebuah mainan yang menyerupai suara binatang yang terbuat dari kaleng bekas sarden. Kaleng itu di lubangi salah satu bagiannya dan bagian yang lainnya dibiarkan saja, kemudian dilubangi dengan paku agar tali (benang kasur) dapat masuk memanjang ke bawah.  Setelah itu basahi benangnya dengan air, lalu tarik benang dan pada saat menarik benang tekankan jari telunjuk dan jempol diantara benang itu sehingga tarikannya tersendat-sendat, nah pada saat ditarik itulah timbul bunyi. Suaranya lucu dan aneh, bisa menyerupai kokok ayam, suara tokek atau suara lainnya tergantung bagaimana cara jari tangan menarik benang yang memanjang itu.

Nah adik-adik, sekarang mari kita buat mainan tersebut sambil mempelajari bagai mana konsep fisika  yang terjadi pada alat tersebut.

Adapun bahan/alat yang akan kita gunakan adalah:
1.       Gelas plastik bekas yang agak besar gelas bekas yang tentunya harus bersih ya
2.       Benang 1 meter
3.       Tusuk gigi

 Cara membuatnya :
1.       Lubangi gelas dengan tusuk gigi.
2.       Masukan benang kasur melalui lubang tadi dan biarkan membentang didalam lubang gelas plastik.
3.       Ikatkan tusuk gigi dengan benang pada bagian luar gelas.
4.       Basahi benang kasur dengan air secukupnya.
5.       Tekan benang kasur dengan kedua jari mulai dari bibir gelas plastik kemudian tarik, aturlah tekanannya untuk mendapatkan bunyi yang diinginkan.

Hasil : Jika pautan benangnya bagus akan terdengar bunyi menyerupai suara binatang seperti : suara kokok ayam, suara tokek, dan jenis suara lainya

Penjelasan :
Pada saat menarik benang kasur, air pada benang kasur berfungsi memperkuat gesekan jari dengan benang kasur sehingga tarikan jari tersendat-sendat seperti sentakan-sentakan kecil akibat gaya tekan jari tangan pada benang. Sentakan-sentakan itu menimbulkan getaran maju-mundur pada bagian atas gelas sehingga membuat molekul-molekul udara didalam gelas plastik juga ikut bergetar maju-mundur sesuai dengan irama tarikan jari kita. Sedangkan gelas itu berlaku seperti spiker (megafon) yang menjalarkan gelombang bunyi ke satu arah.

Nah, adik-adik silahkan mencobanya, semoga berhasil ! fisika untuk sekolah dasar (Untuk SD kelas V dan VI)

Mathematics physics education

Determining average velocity of fungtion of position


Average velocity (v) of a car can be calculated by dividing the displacement (∆r) by the time interval (∆t) taken :



  • Instantaneous velocity (ν) of particle can be calculated from the average velocity with a small interval of time
  • In calculus, the derivate of this equation is easer and can be written as : 
  • So, the instantaneous velocity is the derivative of the position function :
  • In mathematics, the derivative of function   

complete file Mathematics
physics education for High School
Mathematics physics education

HEAT


HEAT CONDUCTORS AND INSULATORS

primary school: HEAT CONDUCTORS AND INSULATORS
Do you still remember about heat ? Heat is form of energy that exist in our daily life. For example : heat from an stove can make water in ktlle boil heat from an iron can make clothes smooth Can you think of another example of heat and its use in your surronding ?
  •  Heat can move from hot objects to cooler Look at following examples and take a look at how heat moves from one abject to another. Heat from fine moves to ketlle. Heat from the ketlle moves to the water and makes the water boil
  • Heat can move from hot objects to cooler Heat from the iron moves to the clothes.
        * It makes the clothes       
        * become smooth
  • Every day the brother and sister always drink a cup of warm milk. To day, sister chooses a cup made from glass. Where brother chooses a cup mad from plastic.
    Sister can not hold the cup because it is too hot, whereas brother does not ?
    Why does siter feel the heat of cup whereas brother does not ?
    It’s because the material of the two cups is different
  • Brather and his friends do an experiment about heat transfer at shool. Four cups, made from different materials, have been preared on the table. ( Glass cup, Plastic cup , Styrofoam cup, and Metal cup )
    Pour hot water into each cup and let it stand for several seconds. Now let’s move the cups using the hand.  Cups that can be held by hand, because they’re not too hot are : Those made of styrofoam andplastic. Whereeas the cup that can not be held by hand, because they’re too hot are : Those made of glass and metal
  • Why does one cup get warmer quicker than the other ?
    Some materials can conduct heat quickly.
    On the other hand, some materials do not conduct heat quickly
    1.Some materials can conduct quickly. That why in few minutes heat from water can be felt on the cup
    2.Some materials do not conduct heat quickly, and it takes longer to become hot
    Materials that can conduct heat better are called conductor. The samples of conductors are : Iron, Alumunium, and Glass.
    Material that do not conduct heat well are called insulator. The samples of insulator are : Plastic, Styrofoam, Wood and Cloth.

good luck >>>> Heat File <<<<<
    HEAT CONDUCTORS AND INSULATORS for primary school

    Respiratory organ, Basics School Class V

    Respiratory organ, Basics School Class V
     oxigen is requered to convert glucose obtained from food into energy



    Primary school, Respiratory organ, Basics School Class V 2012

    STUDENT WORKSHEET

    LEMBAR KERJA SISWA ( LKS )
    MEDAN GRAVITASI
    PERTEMUAN KE 1 dan 2
    Hukum Gravitasi Newton
    Setiap benda di alam semesta menarik benda lain dengan suatu gaya yang
    sebanding dengan hasil kali massa masing-masing benda dan berbanding
    terbalikdengan kuadrat jarak antara kedua benda tersebut”.
    Gaya tari antara kedua benda disebut gaya gravitasi yang besarnya :

    F = G (m1.m2)/r^2
    Dengan :
    m1 = massa benda pertama (kg)
    m2 = massa benda ke dua (kg)
    G = konstanta gravitasi umum (N m2/kg2) = 6,67 . 10 -11 N m2/kg2
    F = gaya gravitasi Newton (N)
    r = jarak antara kedua benda (m)



    Gaya Gravitasi Newton pada suatu titik antara benda-benda yang membentuk sudut

    ●m2
    F21
    FR FR = √(〖F^2〗_21+〖F^2〗_31+ 2〖 F〗_21 .F_31 cos⁡α )
    m1●

    F31
    ● m3



    Percepatan gravitasi atau kuat medan gravitasi adalah gaya gravitasi per satuan massa
    yang dialami sebuah benda

    g = G M/R^2

    g = percepatan gravitasi atau kuat medan gravitasi (N/kg)
    G = konstanta gravitasi umum ( N m2/kg2 )
    M = massa benda (kg)
    R = jarak titik dari benda (m)

    ●m2 Besar kuat medan gravitasi seperti pada gambar samping :
    g21
    gR gR = √(〖g^2〗_21+〖g^2〗_31+ 2〖 g〗_21 .g_31 cos⁡α )
    m1●

    g31 ● m3

    Percepatan gravitasi pada ketinggian tertentu diatas permukaan bumi

    g/go = [ R/(R+h) ]2 atau gb/ga = [ R/(R+h) ]2
    g = gb = percepatan gravitasi pada ketinggian h (m/s2)
    go = ga = percepatan grvitasi pada permukaan bumi (m/s2)
    R = jari-jari bumi (m)
    h = ketinggian benda dari permukaan bumi

    Perbandingan percepatan gravitasi du buah planet

    (gp / gb) ₌ ( mp / mb ) . [ Rb/Rp ]2

    gp = percepatan gravitasi di planet P
    gb = percepatan gravitasi di planet B
    mp = massa benda di planet P
    mb = massa benda di planet B
    Rp = jari-jari benda di planet P
    Rb = jari-jari benda di planet B

    Latihan Soal :

    Gambarlah vector gaya gravitasi pada system benda dibawah ini

    a. A r B 2r C
    О----------------О----------------------------О

    b. A Ө Ө B (1). Resultan di A ?
    (2 ). Resultan di B ?
    (3 ). Resultan di C ?
    Ө C

    c. Resultan di titik P ?
    . P

    A ● ● B
    Benda A massanya 2 kg berada pada jarak 5 m dari benda B yang massanya4,5 kg,
    sedangkan benda C berada diantara A dan B. Jika gaya gravitasi pada C sama dengan nol,
    tentukan jarak A dan C ?

    Diketahui : C
    A ●----------------●---------------------------●B
    FAC FCB
    rAB = 5 m,mA = 2 kg ,
    mB = 4,5 kg,
    FC = 0

    Jika AC = x , maka CB = 5 – x

    ditanya : x = ………….?
    Jawab :

    FAC = FCB
    G (ma.mc)/(r^2 ac) = G (mc.mb)/(r^2 cb)

    ( )/ = ( )/

    ……………. = ……………………
    ………….… = …………………….
    ………………………… = ………..
    …………………………. = ………..
    .…………………………. = 4,5 x2
    ……………………….. = 4,5 x2
    ………………………… = 0
    (……………) + (………….) = 0
    X 1 = ……..
    X2 = ………
    Jadi jarak A dan C adalah ………… m

    Benda A massa 3 kg, B massa 4 kg dan C massa 2 kg. Jarak AB = 4 m dan jarak AC = 5 m
    dan saling membentuk sudut 60o dengan titik tangkap di A. Berapakah resultan gaya gravitasinya ?

    Diketahui : ma = 3 kg; mb = 4 kg ; mc = 2 kg ; rAB = 4m ; rAC = 2 m ; α = 60o
    dan G = 6,67 . 10 -11 Nm2/kg2
    Ditanya : FR = ……………. ?
    Jawab :
    FAB = G (ma.mb)/(r^2 ab) = ………………………………………………………………………………………………………………….

    FAC = G (ma.mc)/(r^2 ac) = …………………………………………………………………………………………………………………

    FR = √(〖F^2〗_AB+〖F^2〗_AC+ 2〖 F〗_AB .F_AC cos⁡α )
    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
    Seorang yang beratnya 80 N jika di permukaan bumi. Bila orang tersebut berada pada
    ketinggian 3 kali jari-jari bumi, berapakah beratnya sekarang ?

    Diketahui : W1 = 80 N; R2 = 3 R1
    Ditanya : W2 = ……….. ?

    Jawab :

    W = G (m1.m2)/r^2


    W1 = (R2 )2
    W2 (R1)2

    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    5. Gaya gravitasi danper cepatan gravitasi /
    medan gravitasi merupakan besaran …………………

    LEMBAR KERJA SISWA
    PERTEMUAN KE …….
    Energi potensial gravitasi adalah usaha untuka melakukan perpindahan benda sejauh r meter.

    EP = W . r = - G (M.m)/r^2 x r = - G (M.m)/r^

    EP = energy potensial gravitasi (joule atau kg m2/s2)
    Potensial gravitasi adalah energy potensial gravitasi per satuan massa
    V = - G M/r^
    V = votensial gravitasi ( joule/kg atau kgm2/s3)
    Energi potensial gravitasi dan Potensial gravitasi merupakan …………………..

    Kelajuan benda untuk mengorbit planet :

    ν =√(GM/R) atau ν = √(g R)

    v = kelajuan benda untuk mengorbit (m/s)
    Persamaan perioda pada gerak planet yang sedang mengorbit adalah :

    T2 = 4π2 R3/GM
    Hokum I Kepler menyatakan : “ Planet bergerak mengelilingi matahari dengan
    lintasan berbentuk elips dan matahari berada dititik focus elipsnya”.
    Hokum II Kepler menyatakan : “ Suatu garis khayal yang menghubungkan
    Matahari dengan planet menyapu luas juring yang sama dalam selang waktu yang sama “.
    Hukum III Kepler menyatakan : “ Perbandingan kuadrat periode terhadap pangkat
    tiga jari-jari orbitnya adalah sama untuk semua planet”.
    Hokum ini ditulis secara matematis :

    T2/R 3 = k atau T2/R3 = 4π2/ GM
    T = perioda revolusi planet ( sekon)
    R = jari-jari orbit planet (meter)
    k = suatu tetapan yang memiliki nilai sama untuk semua planet
    M = massa matahari (kg)
    k = 4π2/GM

    LATIHAN SOAL

    Sebuah satelit dari planet Mars memiliki periode 495 menit. Besarnya massa planet ini
    6.42 .1023 kg, dan G = 6,67 . 10 -11 Nm2/kg2. Berapakah jari-jari orbit satelit tersebut ?

    Diketahui :
    T = 495 menit = ……………….sekon ;
    M = 6,42 . 10 23 kg ;
    G = 6,67 . 10 -11 Nm2/kg2
    Ditanya : R = ………….. ?
    Jawab :

    T2 = 4π2 R3/GM

    R3 = T2 GM / 4π2
    ………………………………………………………………………………………………………………………………………………
    ………………………………………………………………………………………………………………………………………………
    ………………………………………………………………………………………………………………………………………………
    ……………………………………………………………………………………………………………………………………………..

    Tentukan periode Mars mengelilingi matahari, bila jarak Mars ke Matahari 1,5
    kali jari jari bumi ke matahari ?
    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    Pada suatu titik diatas permukaan bumi potensial gravitasinya adalah – 5,12 .
    107 J/kg dan percepatan gravitasi bumi adalah 6,4 m/s2. Jika jari-jari bumi 6.400 km,
    maka hitunglah ketinggian titik tersebut dari permukaan bumi ?
    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    Sebuah system terdiri atas tiga buah bola. Setiap bola massanya 5 kg dan bola
    tersebut terletak di titik sudut sebuah segitiga sama sisi, yang panjang sisinya 20 cm.
    Berapakah besar energy potensial system tersebut ?
    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    Sebuah satelit yang massanya 500 kg mengorbit pada ketinggian 7.000 km diatas
    permukaan bumi. Berapakah kecepatan satelit, jika jari-jari bumi adalah 6.400 km ?
    ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

    Tanggal : ………………………………… Nama Guru : …………………………………

    Nama Siswa : ………………………………… Faraf : …………………………………

    Nilai : …………………………………


    Untuk download LKS  Silahkan  Disini 

    Gaya Angkat Pesawat Terbang

    Gaya Angkat Pesawat Terbang
    Fisika Untuk siswa SD SMP SMA dan SMK

    Pernahkah terpikir, apa yang menyebabkan pesawat terbang yang begitu berat bobotnya bisa naik, dan melayang seperti benda yang ringan ? Nah untuk menjawab pertanyaan itu, marilah kita lakukan percobaan ini  
    Percobaan 1.
    1. Siapkan corong plastik yang transparan dan satu bola pingpong.
    2. Balikkan corong hingga bagian lubang yang besar menghadap ke bawah.
    3. Masukan bola pingpong pada bagian lobang yang besar dan tekan dengan telunjuk hingga menutupi lubang kecilnya.
    4. Tiuplah lubang kecil pada bagian atasnya,kemudian lepaskan tekanan jari telunjuk yang menahan bola pingpong dan atur tiupan sedemikian rupa sehingga bola tidak jatuh.
    Hasil : Bola terapung di dalam Corong seperti benda yang terangkat.

    Penjelasan :
    Semakin cepat udara melewati bola pingpong, semakin keciludara yang ditimbulkannya terhadap bola. Tekanan udara diatas bola pingpong lebih kecil dari pada tekanan udara di bagian bawah bola pingpong. Sementara kecepatan udara diatas pola pingpong lebih besar dibandingkan kecepatan udara di bawah bola pingpong. Tekanan udara yng demikian menggambarkan gaya angkat yang dialami oleh sayap peswat terbang. Ketika kecepatan udara diatas pesawat lebih besar daripada dibawahnya, sehingga timbul tekanan keatas yang disebut gaya angkat pesawat terbang.


    Percobaan 2.
    Ambilah selembar kertas kemudian bentangkan salah satu ujungnya dengan kedua tangan. Tiuplah pada ujung bagian atas kertas dan perhatikan ujung kertas yang terbebas.
    Hasil : ujung kertas yang bebas akan terangkat.


    Selamat mencoba, semoga berhasil dan menjadi lebih senang dengan pelajaran Fisika.
    Sumber : Janice Pratt Van Cleve, Gembira Bermain dengan Fisika ( terjemahan ), Pustaka utama Grafiti,1993

    FISIKA BAB I KINEMATIKA PARTIKEL

    TEST FISIKA
    BAB I KINEMATIKA PARTIKEL
    Untuk kelas SMA 

    1. Gerak sebuah benda memiliki persamaan posisi
    r = (− 6 – 3t)i + (8 + 4t)j. Semua besaran menggunakan satuan dasar SI.
    Dari persamaan tersebut,
    disimpilkan sebagai berikut :
    1. koordinat awal (–6,8) m
    2. kelajuan awal 10 m s–1
    3. lintasannya lurus
    4. perpindahannya 7 m tiap sekon
    Pernyataan yang benar adalah …
    A. (1), (2) dan (3)
    B. (1), (2), (3) dan (4)
    C. (1) dan (3)
    D. (2) dan (4)
    E. (4)

    2. Gerak sebuah benda memiliki persamaan posisi :
    r = (2 + 4t + 4t2) i + (1 + 3t + 3t2) j.
    Semua besaran menggunakan satuan SI.
    Pernyataan-pernyataan berikut berkaitan dengan gerak benda diatas.
    1. Benda memiliki koordinat awal (4,3)m
    2. Setelah 1 sekon perpindahannya 10 m
    3. Benda memiliki percepatan 5 ms-2
    4. Geraknya berupa gerak lurus berubah beraturan
    Pernyataan yang benar adalah ….
    A. (1), (2), dan (3)
    B. (1) dan (3)
    C. (2), (3), dan (4)
    D. (1) dan (4)
    E. (2) dan (4)

    3. Kedudukan sebuah benda titik yang bergerak dalam
    bidang datar dinyatakan oleh persamaan
    r = (5t2 – 2t)i + 6tj dengan ketentuan r dalam meter dan t dalam sekon.
    Nilai percepatan benda pada saat t = 2 sekon adalah …
    A. 6 m s–2
    B. 10 m s–2
    C. 18 m s–2
    D. 24 m s–2
    E. 28 m s–2

    4. Sebuah benda yang semula berada di titik acuan bergerak dengan kecepatan
    v = (2i − 1,5j) m s–1. Setelah bergerak selama 4 sekon, benda berpindah sejauh …
    A. 2 m
    B. 10 m
    C. 12 m
    D. 14 m
    E. 25 m

    5. Sebuah partikel bergerak dengan vektor posisi
    r = ( 2t2 – t) i – (t3 + t) j dalam satuan SI
    Besar kecepatan partikel pada
    t = 1 sekon adalah …
    A. 1 m s–1
    B. 3 m s–1
    C. 4 m s–1
    D. 5 m s–1
    E. 7 m s–1

    6. Posisi sebuah benda dinyatakan dengan
    persamaan r = ( 15t√3 )i + (15 t-5 t2)j m.
    Setelah benda bergerak selama 1,5 sekon kelajuannya menjadi …
    A. 0
    B. 15 m s-1
    C. 11,5√3 m s-1
    D. 22,5 m s-1
    E. 15√3 m s-1

    7. Sebuah partiker berotasi dengan persamaan posisi
    sudut Ө = ( t3- t2 + 5 ) radian, dan t dalam sekon.
    Percepatan sudut partikel pada saat t = 2 sekon adalah …….. rad/sekon2
    A. 2
    B. 4
    C. 8
    D. 10
    E. 15

    8. Percepatan sudut suatu roda dinyatakan oleh persamaan :
    α = (3t + 2) rad/s2. Mula-mula benda diam,
    maka kecepatan sudut rata-rata antara t = 0 dan t = 2 sekon adalah ….. rad/s
    A. 8
    B. 5
    C. 4
    D. 2
    E. 0

    9. Sebua benda bergerak rotasi dengan percepatan sudut tetap 2 rad/s2 ,
    kecepatan awal dan posisi awal masing-masing 5 rad/s dar 10 rad.
    Kecepatan sudut rata-rata selama lima detik pertama adalah …..rad/s
    A. 5
    B. 7
    C. 8
    D. 10
    E. 12
    10. Sebuah benda bergerak melingkar dengan posisi sudut sebagai fungsi
    waktu : Ө = (-4t2 + 12t + 6 ) rad, dan t dalam sekon.
    Kecepatan sudut pada saat t = 3 sekon adalah ……..rad/s
    A. -6
    B. -8
    C. -12
    D. -16
    E. -20

    11. Bola di tendang dengan sudut elevasi α dan kecepatan awalnya Vo,
    bila percepatan gravitasi bumi = g, maka lamanya bola di udara adalah ....
    A. Vo sin α
    g
    B. Vo sin α
    2g
    C. 2Vo sin α
    g
    D. 2Vo sin 2α
    G
    E. Vo sin 2α
    g
    12. Sebuah bola ditendang dengan kecepatan awal 20 m s–1
    dan sudut elevasi 30o. Jika g = 10 ms–2 ,
    jarak mendatar yang dicapai bola adalah…
    A. 20√3 m
    B. 20 m
    C. 10√3 m
    D. 10 m
    E. 5 m

    13. Sebuah peluru ditembakkan dengan kecepatan awal 20 m/s dan
    sudut elevasi 450. Jarak terjauh yang dapat dicapai peluru adalah …
    A. 20 m
    B. 25 m
    C. 30 m
    D. 40 m
    E. 50 m

    14. Sebuah benda dilemparkan dengan sudut elevasi 530 dan
    kecepatan awal 20 m/s (lihat gambar).
    Jika g = 10 m/s2, maka posisi benda setelah bergerak 1,2 detik adalah …
    A. (11,0 ; 15,2) meter
    B. (15,2 ; 11,0) meter
    C. (14,4 ; 12,0) meter
    D. (12,0 ; 10√2) meter
    E. 11,0 ; 15,2) meter

    15. Seorang anak melempar batu dengan kecepatan awal 12,5 m s–1
    dan sudut 30o terhadap horizontal. Jika percepatan gravitasi 10 m s–2,
    waktu yang diperlukan batu tersebut sampai ke tanah adalah …
    A. 0,40 s
    B. 0,60 s
    C. 1,25 s
    D. 1,60 s
    E. 2,50 s

    16. Peluru ditembakkan dengan kecepatan awal 30 m s–1 dan
    membentuk sudut 300 terhadap bidang horizontal.
    Pada saat mencapai titik tertinggi kecepatannya adalah …
    A. 30√3 m s–1
    B. 30 m s–1
    C. 0 m s–1
    D. 15 m s–1
    E. 15√3 m s–1

    17. Sebuah peluru ditembakkan dengan kecepatan awal 100 m s–1
    dan sudut elevasi 300. Jika gravitasi di tempat itu 10 m s–2,
    maka waktu yang diperlukan peluru tersebut untuk mencapai titik terjauh adalah …
    A. 2 sekon
    B. 5 sekon
    C. 6 sekon
    D. 10 sekon
    E. 15 sekon

    18. Sebuah benda dilemparkan dari suatu tempat yang tingginya 40 meter
    di atas tanah dengan kecepatan 40 m s–1 dan sudut elevasi 60o
    terhadap horizontal. Jika g = 10 m s–2 maka tinggi maksimum yang
    dapat di capai benda dari permukaan tanah adalah …
    A. 20 m
    B. 40 m
    C. 60 m
    D. 80 m
    E. 100 m

    19. Sebuah partikel melakukan putaran melalui sebuah
    koordinat kartesius, pada t1 = 0 berada pada koordinat (2,4)
    dan pada t2 = 2 detik berada pada koordinat (8, 6)
    maka vektor kecepatan sudut rata-ratanya adalah ....
    A. 3i + 2j
    B. 4i + 3j
    C. 3i + j
    D. 2i + 4j
    E. 4i + 3j

    20. Percepatan sebuah partikel pada saat t sekon dinyatakan
    dengan persamaan sebagai berikut : α = (3i + 2tj) rad/s2 dengan t dalam sekon.
    Apabila kecepatan sudut awal ωo = (2i + 4j) rad/s,
    maka besar kecepatan partikel pada saat t = 2 sekon adalah ………rad/s
    A. 6
    B. 6√2
    C. 8
    D. 8√2
    E. 10

    selamat mencoba Semoga Bermanfaat ,  
    Download Soal Latihan  FISIKA  BAB I KINEMATIKA PARTIKEL

    GRAVITY FIELD


    Pelajaran fisika medan gravitasi untuk sma





    pelajaran fisika medan gravitasi untuk sma GRAVITY FIELD

    Sunday, January 1, 2012

    Mengubah tinggi-nada suatu bunyi dengan

     Mengubah tinggi-nada suatu bunyi  dengan  percobaan sederhana.
    fisika sekolah dasar 

    Sekarang mari kita lakukan percobaan yang bertujuan untuk  mengetahui apakah tinggi nada bunyi dapat diubah-ubah. Coba sediakan  sebuah sendok yang terbuat dari logam (besi), benang kasur secukupnya (kira-kira  150 cm).
    Caranya : Lakukan dengan bantuan teman (2 orang)
    a.       Ikatkan sendok ditengah-tengah benang.
    b.      gulungkan  ujung benang pada kedua telunjukmu. Usahakan agar benang sama panjang, sehingga sendok tergantung di tengah-tengah.
    c.       Masukkan kedua telunjukmu ke lubang telinga kiri dan kanan, kemudian bungkukkan badan agar sendok tergantung bebas.
    d.      Mintalah teman anda untuk memukul sendok tersebut dan dengarkan.
    e.      Perpendek benang  dengan menggulung kembali benang pada kedua telunjukmu dengan menjaga panjang yg sama sehingga sendok berada ditengah-tengah.
    f.        Mintalah kembali teman anda untuk memukulnya dan dengarkan, apakah ada perbedaan nada bunyi sendok ?
    Hasil percobaan :
    Akan terdengar bunyi  seperti lonceng.
    Penjelasan :
    Logam pada sendok bergetar saat di pukul.  Getaran pada sendok bergerak bolak balik. Pada peristiwa ini , molekul-molekul pada sendok bergerak bolak-balik dan saling bertumbukan sehingga terjadi perpindahan energi dari satu molekul ke molekul lain. Molekul yang bergetar dalam sendok menumbuk molekul-molekul  dalam benang sehingga terjadi perpindahan energi melalui benang ke telinga.
    Perbedaan tinggi nada bunyi yang terdengar telinga disebabkan perbedaan frekuensi (jumlah getaran yang tiba di telinga tiap satu detik). Bunyi nada tinggi akan terdengar jika getaran yang tiba ditelinga frekuensinya banyak, nadanya akan rendah jikan frekuensinya sedikit.
    Benang yang panjang dan pendek menerima energi getaran sendok hampir sama banyaknya. 
    Karena benang pendek lebih sedikit molekulnya, maka setiap molekul benang akan menerima lebih banyak energi getaran sendok dan bergetar lebih cepat, sehibgga memberikan nada lebih tinggi.
    Benang panjang menghasilkan nada lebih rendah, karena mengandung lebih banyak molekul maka energi yang diterima nya lebih sedikit sehingga getarannya lebih lambat.
    Selamat mencobanya, semoga sukses ! mew update 2012

    Sumber :  Physics for Every Kid : 101 Easy Experiments in Motion, Heat, Light, Machines, and Sound, Janice Pratt Van Cleave, 1991 by John Wiley and Sons, Inc.

    Ridge Forge

    Why the helicopter tilted position while on the move ?
    Whatever force happens to helicopter ?

    Note the picture beside.
    When ignited aircraft  engine,  propeller  plane spinning but still not flying.
    This is due to the gravity of the aircraft is still greater than ridge force, so theresultant  force of gravity in the direction of the helicopter..
    Force that occurs in helicopter is:
    a. F = force ridge, the force due to rotation speed 
         of the propeller
    b. W = weight of the helicopter force, force due to
         entire mass of the helicopter due to the   
         influence of gravity earth
    c. R = resultant force, the force of the sum / difference  between ridgepole  with  gravity force helicopter
    If the ridge force greater than gravity object, then the heli will lift up the plane.
    Resultant from ridgepole style propeller with gravity is what will determine thehelicopter moves fig.

    Physics education Ridge Forge for High School
    update 2012

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