Orchid XP v7 wrote:
> There's 300 enemy troops with SMGs, grenades and rocket launchers, not 
> to mention 3 helicopters, and yet 1 lone commando manages to shoot them 
> all down without dying?

That's what always un-immerses me in FPS games. In Quake II (IIRC) you 
wind up basically killing the entire enemy army yourself without ever 
seeing another living teammate.

-- 
   Darren New / San Diego, CA, USA (PST)
     Remember the good old days, when we
     used to complain about cryptography
     being export-restricted?

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>> Bolt it to the Earth, then (assuming you're measuring recoil relative to
>> the Earth) the recoil will be avoided.
>
> http://www.xkcd.com/162/

"Each turn robs the planet of angular momentum"

Unfortunately not...

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Darren New wrote:
> Bill Pragnell wrote:
>> You'd have to design any such gun to be recoilless somehow. 
> 
> Generally by firing something out the back at a similar momentum. Kind 
> of like the open back on a shoulder-launched rocket/bazooka thing.

That's the only method I've ever heard of, but I can't imagine it would 
work well for a hand-held relativistic projectile weapon! You'd end up 
standing at the cusp between two lobes of utter annihilation.

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Darren New wrote:
> Bill Pragnell wrote:
>>>> or the dubious claim that it can fire projectiles at near lightspeed 
>>>
>>> That's what a railgun is for.
>>
>> No it's not. A railgun accelerates a projectile with something like a 
>> linear accelerator. You get a fast-moving slug but I don't think 
>> anyone's under the illusion that it could be relativistic.
> 
> I think it's more that it's the only technology that's likely to be able 
> to accelerate something to relativistic speeds in a reasonable "barrel 
> length."  Certainly an explosives-based lump-in-a-tube cannon won't.

Maybe, but only if it's a very small projectile, and probably only 
useful in a vacuum (see your friction-vapourisation-explosion discussion 
above).

According to a quick shufti on google, a particle with a rest mass of 
1mg would need to be given 4.5 MJ of kinetic energy to get it to 0.01c, 
and about 450 MJ for 0.1c. I guess that's feasible as a weapon...

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scott <sco### [at] laptopcom> wrote:
> "Each turn robs the planet of angular momentum"

> Unfortunately not...

  I don't see, technically speaking, why not.

  Let's assume we have a big object in a weightless space in vacuum
rotating. Can this rotation be stopped by the object itself without
applying external forces?

  The answer is yes. The most obvious way to do this is to fire up some
rockets in specific directions. This causes the rotation to slow down,
basically by expelling material at high speed from the object.

  A slightly less obvious way is to rotate some significant part of the
object at a different speed. Why does this slow down the overall rotation?
It's because part of the angular momentum is converted into heat due to
friction, and this heat dissipation is taken away from this angular momentum.

-- 
                                                          - Warp

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>> "Each turn robs the planet of angular momentum"
>
>> Unfortunately not...
>
>  I don't see, technically speaking, why not.

Because you need angular *acceleration* to "rob the planet of momentum", not 
angular velocity.

Simply spinning at a constant 5000rpm is not going to change the planet's 
momentum, it will stay constant no matter how many times you turn or for how 
long you stay turning.

Of course spinning up to 5000rpm from 0rpm will change the momentum, but 
then spinning back down from 5000 to 0 will have precisely the opposite 
effect.

So, each turn, does not in fact, rob the planet of any momentum.

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scott <sco### [at] laptopcom> wrote:
> Because you need angular *acceleration* to "rob the planet of momentum", not 
> angular velocity.

> Simply spinning at a constant 5000rpm is not going to change the planet's 
> momentum, it will stay constant no matter how many times you turn or for how 
> long you stay turning.

  Take into account air friction and friction from the ground. In order to
maintain the constant turning speed you have to actually accelerate
constantly due to these frictions.

  Basically you can't have anything connected to the plane rotating at
a constant velocity without applying a force to it (because of friction).
And an applied force means acceleration.

-- 
                                                          - Warp

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>> Because you need angular *acceleration* to "rob the planet of momentum", 
>> not
>> angular velocity.
>
>> Simply spinning at a constant 5000rpm is not going to change the planet's
>> momentum, it will stay constant no matter how many times you turn or for 
>> how
>> long you stay turning.
>
>  Take into account air friction and friction from the ground. In order to
> maintain the constant turning speed you have to actually accelerate
> constantly due to these frictions.
>
>  Basically you can't have anything connected to the plane rotating at
> a constant velocity without applying a force to it (because of friction).
> And an applied force means acceleration.

Friction against what?  Newton's 3rd law...

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scott <sco### [at] laptopcom> wrote:
> Friction against what?  Newton's 3rd law...

  Against the ground and the air.

  Friction causes heat, and the energy for that heat must come from somewhere.
I cannot be produced from nothing.

  The answer is that the energy which produces that heat is coming from
the angular momentum, which is thus reduced by a proportional amount.

-- 
                                                          - Warp

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Darren New wrote:
> Orchid XP v7 wrote:
>> There's 300 enemy troops with SMGs, grenades and rocket launchers, not 
>> to mention 3 helicopters, and yet 1 lone commando manages to shoot 
>> them all down without dying?
> 
> That's what always un-immerses me in FPS games. In Quake II (IIRC) you 
> wind up basically killing the entire enemy army yourself without ever 
> seeing another living teammate.

An entire army is sent to the alien homeworld. The aliens wipe out all 
but 1 soldier, who is left armed with only a tiny pistol. Yet he alone 
is able to destroy an entire string of tactically significant targets, 
completely unaided.

Hmm. :-)

I guess the idea is to massage your ego by letting you be the 
super-soldier that nobody can kill.

Neat intro tho...

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