This is start

aneesh yadav wrote:

THAT'S NICE

how to see without glasses

Why ice floats on water?

Generally, solids are denser than liquids of the same substance.  Solid lead, for instance, is denser than liquid lead.  Because it is denser, it sinks.
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ashishsingh27032001.blogspot.com



By Ashish

Saurabh Kumar wrote:onedrive.live.com/redir?resid=24BB2AC50E2B6AED!107&authkey=!AJlp-uC3nziF_N4&ithint=onenote%2c

Hey guys!! This my notes on Sources of energy. Check it out..........

hey anyone tell me about nuclear fission and critical mass i want to know about it more and in detail

Subhankar wrote:

yeah that video his voice and way was definitely amazing man love it

onedrive.live.com/redir?resid=24BB2AC50E2B6AED!107&authkey=!AJlp-uC3nziF_N4&ithint=onenote%2c

Hey guys!! This my notes on Sources of energy. Check it out..........

ashishsingh27032001 wrote:By Ashish

nice video if you want to get your doubts cleared about gravity.

By Ashish

About Force And Laws of Motion


By- Ashish

Jatin Your Answer


Gravity or gravitation is a natural phenomenon by which all things attract one another including stars, planets, galaxies and even light and sub-atomic particles. Gravity is responsible for the formation of the universe (e.g. creating spheres of hydrogen, igniting them under pressure to form stars and grouping them in to galaxies). Without gravity, the universe would be without thermal energy and composed only of equally spaced particles. On Earth, gravity gives weight to physical objects and causes the tides. Gravity has an infinite range, and it cannot be absorbed, transformed, or shielded against.

Gravity is most accurately described by the general theory of relativity (proposed by Albert Einstein in 1915) which describes gravity, not as a force, but as a consequence of the curvature of spacetime caused by the uneven distribution of mass/energy; and resulting in time dilation, where time lapses more slowly in strong gravitation. However, for most applications, gravity is well approximated by Newton's law of universal gravitation, which postulates that gravity is a force where two bodies of mass are directly drawn to each other according to a mathematical relationship, where the attractive force is proportional to the product of their masses and inversely proportional to the square of the distance between them. This is considered to occur over an infinite range, such that all bodies (with mass) in the universe are drawn to each other no matter how far they are apart.

Gravity is the weakest of the four fundamental interactions of nature. The gravitational attraction is approximately 10−38 times the strength of the strong force (i.e. gravity is 38 orders of magnitude weaker), 10−36 times the strength of the electromagnetic force, and 10−29 times the strength of the weak force. As a consequence, gravity has a negligible influence on the behavior of sub-atomic particles, and plays no role in determining the internal properties of everyday matter (but see quantum gravity). On the other hand, gravity is the dominant force at the macroscopic scale, that is the cause of the formation, shape, and trajectory (orbit) of astronomical bodies, including those of asteroids, comets, planets, stars, and galaxies. It is responsible for causing the Earth and the other planets to orbit the Sun; for causing the Moon to orbit the Earth; for the formation of tides; for natural convection, by which fluid flow occurs under the influence of a density gradient and gravity; for heating the interiors of forming stars and planets to very high temperatures; for solar system, galaxy, stellar formation and evolution; and for various other phenomena observed on Earth and throughout the universe.

In pursuit of a theory of everything, the merging of general relativity and quantum mechanics (or quantum field theory) into a more general theory of quantum gravity has become an area of research.
Ashish

Dhananjay your answer

Little Boy was the codename for the type of atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 by the Boeing B-29 Superfortress Enola Gay, piloted by Colonel Paul W. Tibbets, Jr., commander of the 509th Composite Group of the United States Army Air Forces. It was the first atomic bomb to be used in warfare. The Hiroshima bombing was the second artificial nuclear explosion in history, after the Trinity test, and the first uranium-based detonation. It exploded with an energy of approximately 15 kilotons of TNT (63 TJ). The bomb caused significant destruction to the city of Hiroshima.

Little Boy was developed by Lieutenant Commander Francis Birch's group of Captain William S. Parsons's Ordnance (O) Division at the Manhattan Project's Los Alamos Laboratory during World War II. Parsons flew on the Hiroshima mission as weaponeer. The Little Boy was a development of the unsuccessful Thin Man nuclear bomb. Like Thin Man, it was a gun-type fission weapon, but derived its explosive power from the nuclear fission of uranium-235. This was accomplished by shooting a hollow cylinder of uranium over another hollow enriched uranium cylinder by means of a charge of nitrocellulose propellant powder. It contained 64 kg (141 lb) of enriched uranium, of which less than a kilogram underwent nuclear fission. Its components were fabricated at three different plants so that no one would have a copy of the complete design.

After the war ended, it was not expected that the inefficient Little Boy design would ever again be required, and many plans and diagrams were destroyed, but by mid-1946 the Hanford Site reactors were suffering badly from the Wigner effect, so six Little Boy assemblies were produced at Sandia Base. The Navy Bureau of Ordnance built another 25 Little Boy assemblies in 1947 for use by the nuclear-capable Lockheed P2V Neptune aircraft carrier aircraft. All the Little Boy units were withdrawn from service by the end of January 1951.

During the bombings of Hiroshima and Nagasaki by the U.S.A. in World War II, 64 Kg of Highly Enriched Uranium (HEU) was used in each bomb but only 2 Kg of it was detonated in each bomb. Why is it so?

I like that vidio of vk kumar it is so interesting

what is gravity is it present every where

Physicist Flux wrote:

DAV Science Teacher wrote:

This has already been tought by me...

nice

hey guys check this video out

http://0101.nccdn.net/1_5/180/118/06c/energy-collage.jpg

check this out

DAV Science Teacher wrote:

This has already been tought by me...

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