Jump to content

Physics

The world of forces, particles and high-powered experiments.

  1. Started by taylrl,

    If you know everything about events leading up to a future occurance, then surely you can predict its outcome, does this mean that is outcome is predetermined. For example. In the lottery, if you knew the exact weight of the balls, the height they were dropped from, all of the coefficients of friction and all other information, e.g. air resistance etc. then surely you could program it into a computer and find the outcome. This Is already being done, to a certain extent with mapping weather systems in supercomputers. e.g. they predicted the effects of hurricane Katrina to a certain extent. If you had a powerful enough computer, and could program in sufficient information,…

    • 0

      Reputation Points

    • 26 replies
    • 5k views
  2. Does Human Body sustain light speed vehicles? Now a says astrophysicist are trying to invent light speed vehicles for search of extra terrestrials.

    • 0

      Reputation Points

    • 12 replies
    • 1.7k views
    • 3 followers
  3. Started by tylerbrowner,

    I would think that snow boards are faster because they have a much larger over all surface area so the weight distribution would be a lot better so there would be less friction. this would be of cores a perfect run with the same steepness and no imperfection and it would not be groomed.

    • 0

      Reputation Points

    • 1 reply
    • 1.5k views
    • 1 follower
  4. Hey everyone For an engineering project, I am trying to complete an electric circuit using salt water but I don't want to loose my electrodes from corrosion (allow electrolysis to occur)! is this possible? I was thinking of using AC circuit with high frequencies. I can change the type of salt in the electrolyte, the metals of the electrodes or the setup as you advice. Thank you ..

    • 0

      Reputation Points

    • 6 replies
    • 2.2k views
    • 1 follower
  5. My questions mostly concern the history of physics. Who found the formula for kinetic energy [latex]E_k =\frac{1}{2}mv^{2}[/latex] and how was this formula actually discovered? I've recently watched Leonard Susskind's lecture where he proves that if you define kinetic and potential energy in this way, then you can show that the total energy is conserved. But that makes me wonder how anyone came to define kinetic energy in that way. My guess is that someone thought along the following lines: Energy is conserved, in the sense that when you lift something up you've done work, but when you let it go back down you're basically back where you started. So it seems…

    • 0

      Reputation Points

    • 15 replies
    • 2.5k views
    • 2 followers
  6. Heavier, denser materials subject to thousands of years of pounding, grinding and swept by surf... Are they supposed to sink under the lighther silicate sands on a plain beach ? What minerals are typically supposed to lie under the beach sands, down to bedrock or down to whatever stops them from sinking further ?

    • 0

      Reputation Points

    • 2 replies
    • 1.1k views
  7. Do magnets (permanent) become weaker as they are exposed to para-magnetic objects? I was thinking about this after seeing this. I am buying a magnet and wish to know if a magnet (permanent) loses its magnetic domain structure or alignment when exposed to para magnetic materials.

    • 0

      Reputation Points

    • 1 reply
    • 1.2k views
    • 1 follower
  8. Started by Bjarne,

    The earth accelerates towards perihelion and decelerates towards aphelion Furthermore it accelerates by full moon. How can these 2 factors be calculated, so that I for example is able to know the net result right now, or any given date / time

    • 0

      Reputation Points

    • 0 replies
    • 1.2k views
  9. Hello, everyone. This will be my first post in these forums. I am a 23 years old student and I am starting my own business in the following 1-2 months. It will be an escape room. For those unfamiliar, here is a wiki page about this concept - http://en.wikipedia.org/wiki/Real-life_room_escape Essentially a group of persons (usually 2-4) enters a room (or1-3 room appartment) and they have to solve several intellectual, interesting and original tasks to get out of the room. Time limit is usually 60 minutes. I have thought of several tasks (such as finding coordinates where to put several mirrors, which when done correctly, redirect a laser beam, which opens a door to …

    • 0

      Reputation Points

    • 1 reply
    • 1.3k views
  10. If the electric field and boundary conditions are known exactly for a region of space, is it true that there exists only one charge distribution in that region of space that could have produced it? My understanding of the uniqueness theorem in electrostatics is that for a given charge distribution and boundary conditions for a volume, there exists only one (unique) solution to Poisson's equation, and thus the electric field in that volume is uniquely determined. Does the arrow point the other way, too? If we know the field and boundary conditions, is the charge distribution uniquely determined in the volume? Is there a simple example that illustrates why or why not?

    • 0

      Reputation Points

    • 22 replies
    • 3.2k views
  11. Weinberg-Witten theorem states that massless particles (either composite or elementary) with spin [latex]j > 1/2[/latex] cannot carry a Lorentz-covariant current, while massless particles with spin [latex]j > 1[/latex] cannot carry a Lorentz-covariant stress-energy. The theorem is usually interpreted to mean that the graviton ([latex]j = 2[/latex]) cannot be a composite particle in a relativistic quantum field theory. While the argument is so strong and weird, how is it possible? Why can we not construct a theory which is massless charged vector field and therefore carry a Lorentz-covariant current ? And although we assume the second argument is right, which sa…

    • 0

      Reputation Points

    • 1 reply
    • 2.2k views
  12. Started by Ganesh Ujwal,

    When a ray of light is projected, (say) from the surface of Earth to outside in space. The condition is that, there is no obstruction to it till infinity (it travels only in vaccum). My question is that how far can that ray of light go? Also, instead of a ray of light, if I consider a beam of laser with same conditions, then how far can a beam of laser go? Compare both the situations. And does the light(ray of light and beam of laser) stops after traveling some distance or it has no end?

    • 0

      Reputation Points

    • 11 replies
    • 1.8k views
    • 1 follower
  13. Started by AndresKiani,

    Do we know what energy is in Physics? I've thought about this for a long time, but it seems as though energy some what synonymous with motion and potential for motion. This my interpretation from my readings. Potential to do work. Though what causes an object to do work? What is it within the fabrics of that object that allows it do such a thing? Does this relate back to entropy and perhaps the big bang? It seems to me that energy comes from the instability of something to a more stable existence. Thus does this relate somehow to the big bang perhaps, how the general directionality of the universe is from unstable to more stable?

    • 0

      Reputation Points

    • 4 replies
    • 1.9k views
  14. Here are the 2+1D gravitational Chern-Simons action of the connection [latex]\Gamma[/latex] or spin-connection: [latex]S=\int\Gamma\wedge\mathrm{d}\Gamma + \frac{2}{3}\Gamma\wedge\Gamma\wedge\Gamma \tag{1}[/latex] [latex]S=\int\omega\wedge\mathrm{d}\omega + \frac{2}{3}\omega\wedge\omega\wedge\omega \tag{2}[/latex] Usual Chern-Simons theory is said to be topological, since [latex]S=\int A\wedge\mathrm{d}A + \frac{2}{3}A\wedge A \wedge A[/latex] does not depend on the spacetime metric. (1) Are they topological or not? (2) Do they depend on the spacetime metric (the action including the integrand)? (3) Do we have topological gravitational Chern-Simons theory then…

    • 0

      Reputation Points

    • 1 reply
    • 937 views
  15. Started by AndresKiani,

    Yes this is very true unfortunately, I've never in my life taken a physics course.

    • 0

      Reputation Points

    • 8 replies
    • 2.4k views
  16. Could Cyclotron particle accelerator reaches over 120GeV of the ion's kinetic energy? If that cyclotron uses huge diameter of dees and very high frequency for dees. and even using multi-stage cyclotrons

    • 0

      Reputation Points

    • 5 replies
    • 1.5k views
  17. Started by Externet,

    Read somewhere many years ago, that any three of : Temperature, spark, fuel, oxygen Are needed to make fire. Is that imprecise/incorrect ?

    • 0

      Reputation Points

    • 8 replies
    • 1.4k views
  18. Started by Liiia,

    Sooo a friend of mine had a couple questions in mind, if you guys have any possible answers, please do share, give us your thoughts 1- Can there be energy in 0 Kelvin? 2- Can 0 Kelvin exist in the universe? Answers appreciated in advance

    • 0

      Reputation Points

    • 13 replies
    • 2.5k views
  19. A few days ago I started reading Ira Flatow's Present At The Future (On a recommendation), and in the introduction it discusses his misconceptions about why an airplane wing keeps a plane in the air. On the Bernoulli's Principle 'error': Apparently this is a very common error made by physics teachers across America. He says that: I'm not entirely sure this is true. The book doesn't give any math; just this explanation. One of my questions is: How does an airplane's wing make air go down? It doesn't really make sense to me. I have with me a physics textbook I permanantly 'borrowed' from my 8th grade science teacher, and in it it says: It seems that my textboo…

    • 0

      Reputation Points

    • 206 replies
    • 74.5k views
    • 1 follower
  20. I am starting this as a diversion from the increasingly silly thread about flight, but the discussion is meant to be applicable to both liquids and gases. The heading states the question. Answers have implications for the correction to weighing in air, ships stuck on sandbanks, slip gauges, offshore vertical pipes, dams ... the list is long and varied.

    • 0

      Reputation Points

    • 5 replies
    • 1.5k views
  21. Started by robin gras,

    Time series forecasting is of fundamental importance for a variety of domains including the prediction of earthquakes, financial market prediction, and the prediction of epileptic seizures. We present an original approach that brings a novel perspective to the field of long-term time series forecasting. Nonlinear properties of a time series are evaluated and used for long-term predictions. We used financial time series, medical time series and climate time series to evaluate our method. The results we obtained show that the long-term prediction of complex nonlinear time series is no longer unrealistic. The new method has the ability to accurately predict the long-term evo…

    • 0

      Reputation Points

    • 13 replies
    • 2.8k views
    • 1 follower
  22. Started by Sensei,

    Hello! Does somebody performed experiment in which Chlorine gas has been separated to isotopes Chlorine-35 and Chlorine-37, and measured speed of sound independently per isotope.. ? Best Regards!

    • 0

      Reputation Points

    • 1 reply
    • 1.1k views
  23. I have one project of developing setup to lift heavy water at some height. A setup that take less energy as compare to traditional water pumps. I was searching on net and I found giant "water wheels" of ancient times to lift water. Like this one http://en.wikipedia.org/wiki/Norias_of_Hama Is this possible to rotate this with electric motor and make setup to lift water which is efficient than traditional water pumps? I was thinking that due to circular motion, inertia, momentum, centripetal force, etc might be this can be more efficient than traditional water pumps!. I thought it may require more power to move it from rest but once wheel gets momentum then it requires l…

    • 0

      Reputation Points

    • 34 replies
    • 5.1k views
    • 2 followers
  24. Hi guys, I am thinking what science is behind this case. Why 2 men can't lift a 2 ton car but same men with same force/energy can push same mass car for even 1000 meters. Second question is why at start pushing a car requires more energy but later once moved it requires less energy to push same car. Can anyone throw some light on this? Which scientific forces are involved in this and any other example of same forces in our common life? Shaks

    • 0

      Reputation Points

    • 19 replies
    • 3.2k views
    • 3 followers
  25. Started by lia,

    How can speed affect time or mass? Cause speed cannot be measured in space, lightspeed may be static while the other stuff moving at lightspeed. So how can people age differently?

    • 0

      Reputation Points

    • 2 replies
    • 1.6k views

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.