# FTL front collision: how much kinetic energy liberated ?

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#### killium

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<p>Hi, another of my questions lol.... Two spaceships going at 0.8c in reference to a central point between the two, collides together once they reached that point. Of course, because of relativity, the two spaceships will "measure" the speed of the other as 40/41c only. What energy will be released when they collide ? (40/41)*2 or 1.6*2 (assume there is no loss etc..) ?</p><p>&nbsp;</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> </div>

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#### DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Hi, another of my questions lol.... Two spaceships going at 0.8c in reference to a central point between the two, collides together once they reached that point. Of course, because of relativity, the two spaceships will "measure" the speed of the other as 40/41c only. What energy will be released when they collide ? (40/41)*2 or 1.6*2 (assume there is no loss etc..) ?&nbsp;&nbsp; <br />Posted by killium</DIV></p><p>You take the two speeds with respect to the "central point", calculate their relativistic mass ( gamma * rest mass) from that calculate energy from E=mc^2.&nbsp; Now calculate the energy at rest (E = rest mass * c^2).&nbsp; The difference is the kinetic energy.&nbsp; When the two ships collide, inelastically you will "release" the kinetic energies of the two ships.&nbsp; It will be converted into heat and some destruction of molecular bonds as material is ripped and shredded.&nbsp; <br /></p> <div class="Discussion_UserSignature"> </div>

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#### coeptus

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<p>Blammo !</p><p>&nbsp;Thud !</p><p>Kablooey ! </p><p>&nbsp;Whomp !</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p><font color="#ff00ff">If not for bad Pluck, I'd have no Pluck at all . . .</font></p><p> </p><p><font color="#0000ff">This is your vogon, posting under coeptus, and trying IE and Firefox  to see if either is faster with fewer misloads.  Erf !!</font></p><p> </p><p> </p><p> </p> </div>

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#### why06

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Blammo !&nbsp;Thud !Kablooey ! &nbsp;Whomp !&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br /> Posted by coeptus</DIV></p><p>Yeah somethin like that....only without sound so. it would sond something like this.</p><p><em>Ka!-.......................</em><em>cricket........</em><em>cricket................!!!</em></p> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

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#### coeptus

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Yeah somethin like that....only without sound so. it would sond something like this.Ka!-.......................cricket........cricket................!!! <br /> Posted by why06</DIV></p><p>&nbsp;</p><p>The example cited, 2 craft at .8C colliding is rather dramatic.</p><p>&nbsp;</p><p>The kinetic energies involved are immense.&nbsp; The vehicles represent explosive potential far in excess of nuclear fusion reactions.</p><p>&nbsp;</p><p>The initial pulse of X and gamma rays from the impact will induce an enormous ablative concussive reaction in anything nearby.&nbsp; This mega shock would be&nbsp; (briefly) experienced as sound by a human witness.&nbsp; The witness would not survive, however, and would lead to the question, if the blast leaves no survivors, did it make a sound ??</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p><font color="#ff00ff">If not for bad Pluck, I'd have no Pluck at all . . .</font></p><p> </p><p><font color="#0000ff">This is your vogon, posting under coeptus, and trying IE and Firefox  to see if either is faster with fewer misloads.  Erf !!</font></p><p> </p><p> </p><p> </p> </div>

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#### DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;The example cited, 2 craft at .8C colliding is rather dramatic.&nbsp;The kinetic energies involved are immense.&nbsp; The vehicles represent explosive potential far in excess of nuclear fusion reactions.&nbsp;The initial pulse of X and gamma rays from the impact will induce an enormous ablative concussive reaction in anything nearby.&nbsp; This mega shock would be&nbsp; (briefly) experienced as sound by a human witness.&nbsp; The witness would not survive, however, and would lead to the question, if the blast leaves no survivors, did it make a sound ??&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br />Posted by coeptus</DIV></p><p>&nbsp;</p><p>This scenario seems pretty plausible to me, but&nbsp;your wife or girl friend&nbsp;is not in this thread to reply to your post, so&nbsp;are you still wrong ?<br /></p> <div class="Discussion_UserSignature"> </div>

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