Rabu, 16 Maret 2011

Daniel Jacob Radclife

Daniel Jacob Radcliffe (born in London, England, July 23, 1989, age 21 years) is a British actor, best known for playing Harry Potter. Daniel Radcliffe is the son of Alan and Marcia Gersham. He received the award for best actor from 2003 until 2006. He started playing character Harry Potter, when he was 11 years old. Character Harry Potter himself he feels very similar to her character. He played in the film Harry Potter and 2 man named Rupert Grint, who plays Ron Weasley, and Emma Watson plays Hermione Granger, which plays. Because he played in the movie fans flocked in Harry Potter fanatic, particularly women.
He starred in seven films, including Harry Potter, Harry Potter and the philosopher's stone, Harry Potter and the Chamber of secrets, Harry Potter and the order of Azkaban, Harry Potter and the Goblet of fire ", and " Harry Potter and the order of the Phoenix, Harry Potter and the half-blood Prince, Harry Potter and the Deathly " power part 1. And now he is experiencing career final Harry Potter, Harry Potter and the Deathly Hallows: part 2. His income from the game in the series Harry Potter made him the richest young person in Britain. Currently play in the film Harry Potter and the " Socrer stone (magic stone) he makes money £ 250.000, and " series of Harry Potter and the Goblet of fire (Alastor) she received about £ 5.6 million. The series of Harry Potter and the order of the Phoenix he was about 8 million. pounds sterling.

Kamis, 10 Maret 2011

Biografi Albert Einstein's

Albert Einstein's

Albert Einstein was born at Ulm, in Württemberg, Germany, on March 14, 1879. Six weeks later the family moved to Munich, where he later on began his schooling at the Luitpold Gymnasium. Later, they moved to Italy and Albert continued his education at Aarau, Switzerland and in 1896 he entered the Swiss Federal Polytechnic School in Zurich to be trained as a teacher in physics and mathematics. In 1901, the year he gained his diploma, he acquired Swiss citizenship and, as he was unable to find a teaching post, he accepted a position as technical assistant in the Swiss Patent Office. In 1905 he obtained his doctor's degree.

During his stay at the Patent Office, and in his spare time, he produced much of his remarkable work and in 1908 he was appointed Privatdozent in Berne. In 1909 he became Professor Extraordinary at Zurich, in 1911 Professor of Theoretical Physics at Prague, returning to Zurich in the following year to fill a similar post. In 1914 he was appointed Director of the Kaiser Wilhelm Physical Institute and Professor in the University of Berlin. He became a German citizen in 1914 and remained in Berlin until 1933 when he renounced his citizenship for political reasons and emigrated to America to take the position of Professor of Theoretical Physics at Princeton. He became a United States citizen in 1940 and retired from his post in 1945.

After World War II, Einstein was a leading figure in the World Government Movement, he was offered the Presidency of the State of Israel, which he declined, and he collaborated with Dr. Chaim Weizmann in establishing the Hebrew University of Jerusalem.

Einstein always appeared to have a clear view of the problems of physics and the determination to solve them. He had a strategy of his own and was able to visualize the main stages on the way to his goal. He regarded his major achievements as mere stepping-stones for the next advance.

At the start of his scientific work, Einstein realized the inadequacies of Newtonian mechanics and his special theory of relativity stemmed from an attempt to reconcile the laws of mechanics with the laws of the electromagnetic field. He dealt with classical problems of statistical mechanics and problems in which they were merged with quantum theory: this led to an explanation of the Brownian movement of molecules. He investigated the thermal properties of light with a low radiation density and his observations laid the foundation of the photon theory of light.

In his early days in Berlin, Einstein postulated that the correct interpretation of the special theory of relativity must also furnish a theory of gravitation and in 1916 he published his paper on the general theory of relativity. During this time he also contributed to the problems of the theory of radiation and statistical mechanics.

In the 1920's, Einstein embarked on the construction of unified field theories, although he continued to work on the probabilistic interpretation of quantum theory, and he persevered with this work in America. He contributed to statistical mechanics by his development of the quantum theory of a monatomic gas and he has also accomplished valuable work in connection with atomic transition probabilities and relativistic cosmology.

After his retirement he continued to work towards the unification of the basic concepts of physics, taking the opposite approach, geometrisation, to the majority of physicists.

Einstein's researches are, of course, well chronicled and his more important works include Special Theory of Relativity (1905), Relativity (English translations, 1920 and 1950), General Theory of Relativity (1916), Investigations on Theory of Brownian Movement (1926), and The Evolution of Physics (1938). Among his non-scientific works, About Zionism (1930), Why War? (1933), My Philosophy (1934), and Out of My Later Years (1950) are perhaps the most important.

Albert Einstein received honorary doctorate degrees in science, medicine and philosophy from many European and American universities. During the 1920's he lectured in Europe, America and the Far East and he was awarded Fellowships or Memberships of all the leading scientific academies throughout the world. He gained numerous awards in recognition of his work, including the Copley Medal of the Royal Society of London in 1925, and the Franklin Medal of the Franklin Institute in 1935.

Einstein's gifts inevitably resulted in his dwelling much in intellectual solitude and, for relaxation, music played an important part in his life. He married Mileva Maric in 1903 and they had a daughter and two sons; their marriage was dissolved in 1919 and in the same year he married his cousin, Elsa Löwenthal, who died in 1936. He died on April 18, 1955 at Princeton, New Jersey.

Rabu, 09 Maret 2011




Setiap benda yang bergerak mempunyai momentum.
Momentum juga dinamakan jumlah gerak yang besarnya berbanding lurus dengan massa dan kecepatan benda.
Suatu benda yang bermassa m bekerja gaya F yang konstan, maka setelah waktu t benda tersebut bergerak dengan kecepatan :

vt = vo + a . t
vt = vo + . t
F . t = m . vt – m.vo

Besaran F. t disebut : IMPULS sedangkan besarnya m.v yaitu hasil kali massa dengan kecepatan disebut : MOMENTUM

m.vt = momentum benda pada saat kecepatan vt
m.vo = momentum benda pada saat kecepatan vo


Momentum ialah : Hasil kali sebuah benda dengan kecepatan benda itu pada suatu saat.
Momentum merupakan besaran vector yang arahnya searah dengan
Satuan dari mementum adalah kg m/det atau gram cm/det

Impuls adalah : Hasil kali gaya dengan waktu yang ditempuhnya. Impuls merupakan
Besaran vector yang arahnya se arah dengan arah gayanya.

Perubahan momentum adalah akibat adanya impuls dan nilainya sama dengan impuls.



Misalkan benda A dan B masing-masing mempunyai massa mA dan mB dan masing-masing bergerak segaris dengn kecepatan vA dan vB sedangkan vA > vB. Setelah tumbukan kecepatan benda berubah menjadi vA’ dan vB’. Bila FBA adalah gaya dari A yang dipakai untuk menumbuk B dan FAB gaya dari B yang dipakai untuk menumbuk A, maka menurut hukum III Newton :

FAB . t = - FBA . t
(impuls)A = (impuls)B

mA vA’ – mA vA = - (mB vB’ – mB vB)

mA vA + mB vB = mA vA’ + mB vB’

Jumlah momentum dari A dan B sebelum dan sesudah tumbukan adalah sama/tetap. Hukum ini disebut sebagai HUKUM KEKEKALAN MOMENTUM LINIER.


Pada setiap jenis tumbukan berlaku hukum kekekalan momentum tetapi tidak selalu berlaku hukum kekekalan energi mekanik. Sebab disini sebagian energi mungkin diubah menjadi panas akibat tumbukan atau terjadi perubahan bentuk :

Macam tumbukan yaitu :

Tumbukan elastis sempurna, yaitu tumbukan yang tak mengalami perubahan energi.
Koefisien restitusi e = 1

Tumbukan elastis sebagian, yaitu tumbukan yang tidak berlaku hukum kekekalan energi mekanik sebab ada sebagian energi yang diubah dalam bentuk lain, misalnya panas.
Koefisien restitusi 0 < e < 1

Tumbukan tidak elastis , yaitu tumbukan yang tidak berlaku hukum kekekalan energi mekanik dan kedua benda setelah tumbukan melekat dan bergerak bersama-sama.
Koefisien restitusi e = 0

Besarnya koefisien restitusi (e) untuk semua jenis tumbukan berlaku :

vA ; vB = kecepatan benda A dan B setelah tumbukan
vA ; vB = kecepatan benda A dan B sebelum tumbukan

Energi yang hilang setelah tumbukan dirumuskan :

Ehilang = Eksebelum tumbukan - Eksesudah tumbukan

Ehilang = { ½ mA vA2 + ½ mB vB2} – { ½ mA (vA’)2 + ½ mB (vB’)2}

Tumbukan yang terjadi jika bola dijatuhkan dari ketinggian h meter dari atas lantai.

Kecepatan bola waktu menumbuk lantai dapat dicari dengan persamaan :
vA =
Kecepatan lantai sebelum dan sesudah tumbukan adalah 0.
vB = vB’ = 0
Dengan memasukkan persamaan tumbukan elstis sebagian :

diperoleh : atau

dengan demikian diperoleh :

h’ = tinggi pantulan h = tinggi bola jatuh.

Untuk mencari tinggi pantulan ke-n dapat dicari dengan : hn = h0 e2n