From: David Shaw
>
> I have never attempted relativistic calculations before and wondered if
> I have this right.
>
> I am currently reading John Ringo's 'Gust Front' in which a ground
> based anti-starship weapon is described as firing bars of depleted
> uranium, 100mm in diameter and two metres long at a muzzle velocity of
> 0.3c.
>
> I make this a KE of 1.302 exa-Joules, equivalent to a touch over 311MT
> of TNT.  Is this right?  And would such a weapon system really be
> feasible within an Earth-standard atmosphere?

It's John Ringo. *Never* do the math. In any case, no, it won't work, I'm not sure if it will even escape the atmosphere, but even if it does, it will do so as a rapidly expanding cone, not a solid projectile.