Recent content by jack616

  1. J

    Why the speed of light in the equation?

    Dave ok I can accept c is the universises speed limit what I don't understand is why a speed limit is any part of why mass=energy or vice versa. If a mass is converted into energy why does the speed of light have anything to do with calculating how much energy there is?
  2. J

    Why the speed of light in the equation?

    sorry people I got mixed up replying to incoming answers - I'm not meaning to be combative here -
  3. J

    Why the speed of light in the equation?

    Thanks - but I ask the question because that's the question I'd like an answer to. So perhaps someone else can explain the relationship ? I realize it's tricky to explain some concepts. And I'm not questioning that it IS the case. I'm trying to understand why there is even a...
  4. J

    Why the speed of light in the equation?

    Curious Why does the equivalence of mass/energy involve the speed of light at all? Is it because Einstein discovered that this was simply the correct multiplier or was there some other reason to connect the speed of light to the relationship?
  5. J

    How to calculate impact/stopping power energies

    Hi MrCedgy - thanks for the response. You are right in that I can ignore the more intricate data such as friction etc. Put simply the final goal is to be able to point at a material and say something like "An english longbow arrow should be deflected by X cm thickness of Y material hanging...
  6. J

    How to calculate impact/stopping power energies

    I hope this is a good place to ask this: I'm trying to model how an object such as a kevlar vest performs in stopping a high velocity projectile such as a bullet. I have only basic knowledge of energy and momentum etc. but can learn if directed. I can calculate the Ke of the bullet...
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