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Sensei

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Everything posted by Sensei

  1. Deepak Kapur, do you saw Newton's cradle? http://en.wikipedia.org/wiki/Newton's_cradle It costs less than $10 in western countries, and allows visualizing conservation of momentum (while interaction) between objects with the same mass, or conservation of momentum between objects with different masses, etc. etc.
  2. Actually both wood and iron are made of protons, neutrons and electrons. Simply their configurations are different. There is no two pieces of irons with equal structure (due to f.e. contamination). and there is no two pieces of woods with equal structure. They are just more or less similar, but never equal. Like finger prints. First of all, you should start from analysis of what acceleration and velocity is. Velocity is change of position of measured object over time. f.e. we measure object to be at locations: at t=0 x=0 at t=1 x=10 at t=2 x=20 at t=3 x=30 We can subtract locations of object at different times x(t1)-x(t0) to receive distance object traveled (in meters). If we will then divide it by t1-t0 (in seconds), we will receive velocity (in meters per seconds). v=(x(t1)-x(t0))/(t1-t0) so position of object at time t is x(t)=x(0)+v*t = x(t0) + (x(t1)-x(t0))/(t1-t0) * t Velocity is constant in this example. Thus acceleration is 0, and force is 0. Acceleration can be calculated by taking two velocities at two different times: Imagine measured data: t=0 v=0 t=1 v=1 t=2 v=2 t=3 v=3 Velocity is increasing over time. Acceleration is a=(v(t1)-v(t0))/(t1-t0) Velocities in meters/seconds divided by seconds, gives acceleration in meters/seconds^2. If v(t1) is equal to v(t0), velocity is constant, and we have no acceleration. Force in Newtons is mass in kilograms multiplied by acceleration in meters per seconds^2. Momentum is p=m*v [kg*m/s] So force will be also F=(p(t1)-p(t0))/(t1-t0) Change of momentum over time.
  3. You are bored by knowledge. Apparently you're on wrong forum. Try TMZ.com or so..
  4. You want to make theory of everything, and you don't even know what is ionization energy... what does mean spectral line... etc. etc.
  5. C10H15NO is formula of many different substances: http://en.wikipedia.org/wiki/C10H15NO
  6. Megatons of what? Big Bang was not explosion. What we call explosion on Earth is release of energy stored in chemical bonds and production of oxides in large quantity that are accelerated to high velocities.
  7. Sensei means teacher in Japanese. Read links that I gave you above. It will enlighten you a bit.
  8. No. You first have to learn physics. When you will know everything what typical student knows after several years of education, then it's time for your own hypothesis.
  9. We can speak only how strong or weak is weak force in comparison to other forces, electrostatic, magnetic and gravitation. Big Bang is not force. More info about electrostatic force will provide Coulomb's Law http://en.wikipedia.org/wiki/Coulomb%27s_law Weak force is not uniform in the all particles. Some particles are stable (example is proton/antiproton and electron/positron), some other are theorized to be stable because nobody detected them to decay (Deuterium, Helium-3, Helium-4 f.e.), and some others are unstable. None chemical element has all isotopes stable. These unstable particles have measured half-life time. Imagine 1000 unstable particles at time t0 after half-life time (t0 + half-life) we have 500 particles, after another half-life time (t0 + half-life + half-life ) we have 250 particles, and so on, so on. Half-life article to read if you have not already http://en.wikipedia.org/wiki/Half-life Radioactive decay article to read http://en.wikipedia.org/wiki/Radioactive_decay Isotope article to read: http://en.wikipedia.org/wiki/Isotope Radioactive decays of chemical elements we can split to couple common methods: The most popular is beta decay minus and beta decay plus. Beta decay minus is emitting electron and antineutrino, Beta decay plus is emitting positron and neutrino. http://en.wikipedia.org/wiki/Beta_decay Another one is proton emission: http://en.wikipedia.org/wiki/Proton_emission and neutron emission: http://en.wikipedia.org/wiki/Neutron_emission Heavier elements decay model is alpha decay http://en.wikipedia.org/wiki/Alpha_decay More exotic decay is double beta decay http://en.wikipedia.org/wiki/Double_beta_decay and gamma emission http://en.wikipedia.org/wiki/Gamma_ray Other modes are described in radioactive decay article.
  10. anonymousone, you should be at stage of asking questions about physics. Not creating your own pet theories. You're behaving like your would never attend to primary school, not to mention high, and studies. It's unbelievable to mix all units and don't understanding what is dimensional analysis, how to convert units etc. etc. That's primary school knowledge here. Ask question in separate thread, and it'll be answered, if it's well established knowledge. f.e. "how to calculate decay energy?" f.e. "how do we know that proton has 938 MeV energy?" etc. etc. Anything that you obviously don't know..
  11. Sensei

    vector

    Not sure what do you meant. But on graph you showed acceleration. At t=0 v=0.0 m/s At t=1 v=0.5 m/s At t=2 v=1 m/s 2D vector needs 2 components. 3D vector needs 3 components. and so on, with higher dimensions. Scalar velocity is equal to: sqrt(x^2 + y^2) for 2D vector sqrt(x^2 + y^2 + z^2) for 3D vector and so on, with higher dimensions.
  12. You're talking about obvious, must have, things that should be done with the all data coming from $_GET/$_POST/$_COOKIE etc. (not just session id). Checking IP is not replacement for basic checks, but yet another level of security. All mine Internet bank accounts, and stock market brokers that I am using, are utilizing this technique. You cannot be logged to the same account from two different computers at the same time. Good secured services refuse it immediately. They ask you "you're logged from IP x.x.x.x, do you want to terminate session and open new one?".. Even better is making history of logging with IP recorded. And showing this info to user when he/she is starting session. User will be immediately warned about logging somebody with "wrong" IP, at wrong date and time.
  13. Do you meant 250 thousands or 250? I can't believe in second without serious issue in program.. I am often programming particles, and putting them to octree/kd-tree is obvious standard procedure of speeding them up.. If you "forgot" to turn Floating Point Model: Fast, instead of default Precise, this also can cause several hundred percent slowdown.
  14. Session id stored in cookie should be id to database entry in currently open session table. Database record should store IP address of owner of session, and code should check whether db IP matches with what is clients IP. This will make sure that even if somebody intercept cookie value, he/she won't be able to use it, because their IP will be different than original client that opened session. As long as they didn't intercept whole client network and are able to show up as the same IP..
  15. Cubic lightyears? Light year is not unit. Do you meant m^3 * s^-3? or m^3 (simply volume)? Do you really meant "x = ed = f" Before editing there was "x*e*d=f" Either way, units don't match between sides of equation.. How can you say that energy x in Joules is equal to force f in Newtons.. ?
  16. Energy has unit Joules [J], or electronVolts [eV]. How can you add it to variable that has unit Newtons [N]?
  17. But quantity of particles is unitless, isn't?
  18. All a,b,c,x,y,z are forces in Newtons [N]? So how can you write "b is the ammount of fusion a star has done (how much mass has converted to energy over that star/blackholes life span from start to present)" "Amount of fusion" is in what unit? Is it quantity of particles that fused in star?
  19. What are UNITS of your variables.. Is that too hard question?
  20. anonymousone, so you have basically no idea what we are talking about when we are saying about providing math formulas to confirm theory.. Equation must have correct units. You cannot mix length, with mass, and time, and energy, forces, charges etc. just like that. Show units of a,b,c,x,y,z etc.
  21. Take piece of iron. It doesn't attach to any other iron. It's no magnet, yet. Attach to one of its end small neodymium magnet. Now whole piece of iron is attaching to iron. Take off neodymium magnet, and it's no longer attaching to iron. Take piece of iron, roll up wire on it. Pass current through wire. Whole piece of iron is becoming magnet (electromagnet). Until current is flowing through wire, it's attracting or repelling to/from other magnets or iron.
  22. So the correct link is https://www.youtube.com/watch?v=WN1Wnkm2_Zc https://www.youtube.com/watch?v=WN1Wnkm2_Zc You can't change size of letters in links (it had all characters lower case). Do I need to mention it doesn't work? I have just tried it with 18 powerful neodymium magnets.
  23. None of your youtube video links work (posts #45 #55). "Movie doesn't exist" etc. comment I see.
  24. If you have voltage difference f.e. 2.5 V and you will attach to it f.e. green LED which is emitting green photon with 532 nm. Energy of single emitted photon is E=h*c/wavelength=4.135667*10^-15*299792458/532*10^-9=2.33 eV. Electron in such circuit has kinetic energy 2.5 eV at the beginning. LED is emitting photon with 2.33 eV. So electron after emitting such photon will have 2.5-2.33 = 0.17 eV kinetic energy. It's called voltage drop on element. http://en.wikipedia.org/wiki/Voltage_drop If you will start playing with voltage of circuit, you will see that if electrons have too small kinetic energy (less than 2.33 eV in our case), LED will simply stop emitting light, and no current will be flowing through whole circuit (electrons can't pass through LED, which is blocking them). So, electrons flowing in circuit from negative electrode through electronic elements they lose their kinetic energy (emitting photons etc.), giving part of energy to wires heating them up a bit, and at the end, they end up in positive electrode. Quantity of electrons that was at beginning (on negative electrode), matches quantity of electrons at the end (positive electrode).
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