Does gravity travel instantaneously?
Does gravity travels instantaneously? Or it travels equal to the speed of light.
Answer:
No clear answer now. If we believe in the Theory of relativity, Gravity (Gravitational Waves travel with the same speed as that of light in vacuum. If gravitons are like photons, then it makes sense too.
However I invite you to think more and post your thoughts as comments here. Let the discussion begin.
I found the following links to know more
- http://metaresearch.org/cosmology/speed_of_gravity.asp
- http://en.wikipedia.org/wiki/Speed_of_gravity
- http://www.desy.de/user/projects/Physics/Relativity/GR/grav_speed.html
Categories: +2 Physics, General Physics, Gravitation, interesting question Tags: answer, Auto, desy, discussion, Draft, Gravitational, gravitational waves, photons, speed, speed of gravity, theory of relativity, waves
Motion in a vertical circle and conservation of energy
A stone tied to a string of length l is whirled around a vertical circle with the other end of the string at the centre. At a certain instant of time the stone is at the lowest position and has a speed u. What is the magnitude of change in its velocity as it reaches a position where the string is horizontal?
Answer:
Let’s assume that the potential energy at the lowest position be zero. So, when the string is horizontal, the stone has risen by a vertical height l, the length of the string which is also the radius of the vertical circle.
If v is the magnitude of velocity at the horizontal position, then according to the law of conservation of energy,
KE+PE at the lowest position = KE+PE at the horizontal position
[latex]\frac{1}{2}mu^{2}=\frac{1}{2}mv^{2}+mgl[/latex]
From the equation above, v-u can be calculated.
[latex]v=\sqrt{u^{2}-2gl}[/latex]
The following links will help you for deeper understanding and you can browse through some solved problems from the topic too.
Categories: Answers, ANSWERS TO QUESTIONS FROM VISITORS, CLASS XI, energy loss, energy motion, Exam Help, General Physics, IIT JEE, Interesting Questions, motion work, Physics Homework, Plus Two Physics, power and energy, Problem Solving, Problems, Soved Numerical Problems Tags: Auto, centre, conservation of energy, law of conservation, law of conservation of energy, magnitude, motion, motion laws, position, stone, vertical circle, vertical height
Addition of vectors – can you add 3 unit vectors to get a unit vector ?
“Can you add 3 unit vectors to get a unit vector ? discuss in terms of velocity, force etc”
-Sindhuja posted
The answer is yes. Please find a detailed description on addition of vectors with examples and exercises at the following links.
- http://www.physchem.co.za/Vectors/Addition.htm
- http://www.physchem.co.za/Vectors/Physical%20Examples.htm
- http://www.physicsclassroom.com/class/vectors/u3l1b.cfm
- http://www.walter-fendt.de/ph14e/resultant.htm
- http://canu.ucalgary.ca/map/content/vectors/addition/explain/tiptail/
- http://www.physicsclassroom.com/morehelp/vectaddn/practice.cfm
Categories: Answers, Ask Physics, CBSE, CLASS XI, General Physics, Vectors Tags: physics fundamentals, vector, vector addition, vectors
When several transparent materials are kept above each other, the resultant behaves like an opaque object.Why?What’s the Optics behind it?
When light falls on a object, three things happen -
- A part of the light is absorbed
- Another part is reflected ad
- The remaining part is transmitted.
A transparent medium transmits most of the light incident on it. However, it absorbs a small part as well as reflect a small part.
Therefore, when a number of transparent sheets are stacked, the amount of light absorbed will be considerably large and the arrangement tends to be opaque.
Categories: ANSWERS TO QUESTIONS FROM VISITORS, General Physics Tags: opaque, optics, transmission, transparent
Take an online test from Kinematics and get grading instantly
Click Here to take the online test. The link will open in a new window.
Categories: General Physics Tags: test online
All Nobel Laureates in Physics
Click on the names to know more on the Nobel Laureates in Physics
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- Charles K. Kao, Willard S. Boyle, George E. Smith
- Yoichiro Nambu, Makoto Kobayashi, Toshihide Maskawa
- Albert Fert, Peter Grünberg
- John C. Mather, George F. Smoot
- Roy J. Glauber, John L. Hall, Theodor W. Hänsch
- David J. Gross, H. David Politzer, Frank Wilczek
- Alexei A. Abrikosov, Vitaly L. Ginzburg, Anthony J. Leggett
- Raymond Davis Jr., Masatoshi Koshiba, Riccardo Giacconi
- Eric A. Cornell, Wolfgang Ketterle, Carl E. Wieman
- Zhores I. Alferov, Herbert Kroemer, Jack S. Kilby
- Gerardus ‘t Hooft, Martinus J.G. Veltman
- Robert B. Laughlin, Horst L. Störmer, Daniel C. Tsui
- Steven Chu, Claude Cohen-Tannoudji, William D. Phillips
- David M. Lee, Douglas D. Osheroff, Robert C. Richardson
- Martin L. Perl, Frederick Reines
- Bertram N. Brockhouse, Clifford G. Shull
- Russell A. Hulse, Joseph H. Taylor Jr.
- Georges Charpak
- Pierre-Gilles de Gennes
- Jerome I. Friedman, Henry W. Kendall, Richard E. Taylor
- Norman F. Ramsey, Hans G. Dehmelt, Wolfgang Paul
- Leon M. Lederman, Melvin Schwartz, Jack Steinberger
- J. Georg Bednorz, K. Alex Müller
- Ernst Ruska, Gerd Binnig, Heinrich Rohrer
- Klaus von Klitzing
- Carlo Rubbia, Simon van der Meer
- Subramanyan Chandrasekhar, William A. Fowler
- Kenneth G. Wilson
- Nicolaas Bloembergen, Arthur L. Schawlow, Kai M. Siegbahn
- James Cronin, Val Fitch
- Sheldon Glashow, Abdus Salam, Steven Weinberg
- Pyotr Kapitsa, Arno Penzias, Robert Woodrow Wilson
- Philip W. Anderson, Sir Nevill F. Mott, John H. van Vleck
- Burton Richter, Samuel C.C. Ting
- Aage N. Bohr, Ben R. Mottelson, James Rainwater
- Martin Ryle, Antony Hewish
- Leo Esaki, Ivar Giaever, Brian D. Josephson
- John Bardeen, Leon N. Cooper, Robert Schrieffer
- Dennis Gabor
- Hannes Alfvén, Louis Néel
- Murray Gell-Mann
- Luis Alvarez
- Hans Bethe
- Alfred Kastler
- Sin-Itiro Tomonaga, Julian Schwinger, Richard P. Feynman
- Charles H. Townes, Nicolay G. Basov, Aleksandr M. Prokhorov
- Eugene Wigner, Maria Goeppert-Mayer, J. Hans D. Jensen
- Lev Landau
- Robert Hofstadter, Rudolf Mössbauer
- Donald A. Glaser
- Emilio Segrè, Owen Chamberlain
- Pavel A. Cherenkov, Il´ja M. Frank, Igor Y. Tamm
- Chen Ning Yang, Tsung-Dao Lee
- William B. Shockley, John Bardeen, Walter H. Brattain
- Willis E. Lamb, Polykarp Kusch
- Max Born, Walther Bothe
- Frits Zernike
- Felix Bloch, E. M. Purcell
- John Cockcroft, Ernest T.S. Walton
- Cecil Powell
- Hideki Yukawa
- Patrick M.S. Blackett
- Edward V. Appleton
- Percy W. Bridgman
- Wolfgang Pauli
- Isidor Isaac Rabi
- Otto Stern
- The prize money was with 1/3 allocated to the Main Fund and with 2/3 to the Special Fund of this prize section
- The prize money was with 1/3 allocated to the Main Fund and with 2/3 to the Special Fund of this prize section
- The prize money was with 1/3 allocated to the Main Fund and with 2/3 to the Special Fund of this prize section
- Ernest Lawrence
- Enrico Fermi
- Clinton Davisson, George Paget Thomson
- Victor F. Hess, Carl D. Anderson
- James Chadwick
- The prize money was with 1/3 allocated to the Main Fund and with 2/3 to the Special Fund of this prize section
- Erwin Schrödinger, Paul A.M. Dirac
- Werner Heisenberg
- The prize money was allocated to the Special Fund of this prize section
- Sir Venkata Raman
- Louis de Broglie
- Owen Willans Richardson
- Arthur H. Compton, C.T.R. Wilson
- Jean Baptiste Perrin
- James Franck, Gustav Hertz
- Manne Siegbahn
- Robert A. Millikan
- Niels Bohr
- Albert Einstein
- Charles Edouard Guillaume
- Johannes Stark
- Max Planck
- Charles Glover Barkla
- The prize money was allocated to the Special Fund of this prize section
- William Bragg, Lawrence Bragg
- Max von Laue
- Heike Kamerlingh Onnes
- Gustaf Dalén
- Wilhelm Wien
- Johannes Diderik van der Waals
- Guglielmo Marconi, Ferdinand Braun
- Gabriel Lippmann
- Albert A. Michelson
- J.J. Thomson
- Philipp Lenard
- Lord Rayleigh
- Henri Becquerel, Pierre Curie, Marie Curie
- Hendrik A. Lorentz, Pieter Zeeman
- Wilhelm Conrad Röntgen
Categories: General Physics Tags: Nobel Prize
