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   sci.physics      Physical laws, properties, etc.      178,769 messages   

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   Message 178,715 of 178,769   
   Thomas 'PointedEars' Lahn to Stefan Ram   
   Re: conservation laws   
   10 Feb 26 18:44:16   
   
   From: PointedEars@web.de   
      
   Stefan Ram wrote:   
   > john larkin  wrote or quoted:   
   >>> E = mc^2   
   >> Exactly. Mass/energy conversion is one way to create or destroy some   
   >> mass in my cannonball.   
   >   
   >   "E = mc^2" does not mean, "Mass can be converted to energy and/or   
   >   vice versa". It means, "When the momentum of a system is zero,   
   >   its energy is its mass (up to a conversation factor of c^2).".   
      
   Correct.   
      
   >   In general, the formula for a non-zero momentum p is (with c=1):   
   >   
   > E^2 = m^2 + p^2,   
      
   Yes.   
      
   >   and since E and p are conserved, m must also be conserved.   
      
   No, that is precisely what it does NOT mean.   
      
   > So this   
   >   tells us, "Mass is conserved.",   
      
   No.   
      
   --   
   PointedEars   
      
   Twitter: @PointedEars2   
   Please do not cc me. / Bitte keine Kopien per E-Mail.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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