Recent content by krysith

  1. K

    Help: Motivation, career advice needed.

    Well, if you are asking random people on the internet how to deal with your inner motivations, I figure that's a sign you're hard up and probably do really need to figure out how to help yourself. First, ask yourself why you got into ME in the first place. If it was because you wanted to...
  2. K

    Best vac pump for boiling water

    Could a mod, mentor, or admin please move this post to a sub-forum where it is more likely to receive a reply? Thank you
  3. K

    Best vac pump for boiling water

    Hello all, I am seeking advice on the best, relatively cheap vacuum pump to pump water vapor from the 2 kPa range to the 100 kPa range. Essentially any pump that would work well at boiling water at room temperature would work for me. I'm hoping that someone on here may have done that as a...
  4. K

    Difference between being a nuclear engineer or a physicist when working on fusion.

    In addition to GA, there are often smaller scale fusion projects in the private sector. Some of them fly under the radar, so unless you know about them, you may not hear about them. General Fusion is one of the ones that gets a lot of press recently; I don't want to broadcast the existence of...
  5. K

    Basic question on induced emf

    I think I understand now why you are having doubts. The infinitely low resistance is throwing off your physical intuition. Remember, you cannot use Ohm's Law to calculate the current in a superconductor. So thinking that a high rate of change of flux means a high induced voltage means a high...
  6. K

    Basic question on induced emf

    You are correct that the induced field in the loop will oppose the field of the magnet. However, you forget to include the fact that the magnet has moved closer to the loop, which means that there is more flux from the magnet contained within the loop (at least if you stop moving it before it...
  7. K

    Does a shrinking disk grow in the z-direction?

    If you are using a chemical reaction which has an end-product which has a higher density than the initial reactants, then some transfer of material is occurring as a result of the chemical action. Even if it is internal to the structure, there is some movement of atoms, even if only from one...
  8. K

    The impact of a punch

    Yes, in short you are correct that the impact force of a punch is proportional to the mv^2 of the arm. Of course, there are some additional small corrections that you could apply due to deformation effects. For example, the stopping displacement L is not a constant, but will increase slightly...
  9. K

    Earthquake simulation

    Basic Advice: start off with a flat surface. Use the input from the ipad to shake this flat surface in x,y,z directions. On the flat surface, construct "buildings" which are comprised of rigid body blocks of different sizes. Give each of these rigid bodies a mass - you need inertia for the...
  10. K

    Lazy Layman

    Replying as a lazy physicist, I can tell you that the answer you are looking for is here: http://en.wikipedia.org/wiki/Virtual_particle
  11. K

    Heated coat

    A typical person puts out around 100 watts of heat energy. If you insulate that properly, you will do much better than providing a heating element. However, insulating that properly and still allowing them to breathe is the challenge. Saying that the coat is "well insulated", and then...
  12. K

    Latent Heat of Vaporization /w Temperature

    I'm not sure that the molecular viewpoint is going to be all that informative for you, because the reason has much more to do with the gas that the water vaporizes into. At 100 C, when water boils or evaporates, it turns into 100 C, 1 atm pressure water vapor. At 10 C, when water boils...
  13. K

    Electricity use:Saving by turning lights/power on/off

    Very true. I'm wondering if the original question had been posted in July if there would be as many responses talking about "free heating". Remember that if you are running your air conditioning (as some of us are right now), that every watt saved in lighting also saves about a third of a watt...
  14. K

    Maximal velocity of atoms

    It would first help to know if you are looking for a velocity achieved here on earth or if astronomical sources count. I don't know if they are the fastest ions on earth, but beam injection linacs at CERN or Fermilab routinely use beams of negative hydrogen ions in the hundreds of MeV range...
  15. K

    Falling superconductor in a magnetic field

    I think that it is okay to switch the frames of reference so that the superconductor is moving and the magnet is not. Since we are simply considering forces it doesn't really matter which of the objects is accelerated. However, there is one other big difference between the a sample of...
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