Energy vs Projectile

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The_Nice_Guy
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Post by The_Nice_Guy »

As for microgravity combat, there's always the small rocket launcher, or gyrojet cannon. I think it's considered a projectile weapon, right?

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Post by Admiral Valdemar »

The_Nice_Guy wrote:As for microgravity combat, there's always the small rocket launcher, or gyrojet cannon. I think it's considered a projectile weapon, right?

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In Zero G I would highly reccomend you use a low recoil weapon like a recoilless rifle or laser lest you want to become space debris.
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Post by Kuroneko »

Admiral Valdemar wrote:In Zero G I would highly reccomend you use a low recoil weapon like a recoilless rifle or laser lest you want to become space debris.
How much recoil does a recoilless rifle actually have? IIRC it uses venting from the back to cancel out the force from the projectile, but that it could cancel out the force to negligible levels seems much too optimistic to me.

By my calculation, a laser has recoil of 0.750 pounds per gigawatt of the beam. That's quite miniscule, unless you have a truly horrendous laser.
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Post by Admiral Valdemar »

Kuroneko wrote:
Admiral Valdemar wrote:In Zero G I would highly reccomend you use a low recoil weapon like a recoilless rifle or laser lest you want to become space debris.
How much recoil does a recoilless rifle actually have? IIRC it uses venting from the back to cancel out the force from the projectile, but that it could cancel out the force to negligible levels seems much too optimistic to me.

By my calculation, a laser has recoil of 0.750 pounds per gigawatt of the beam. That's quite miniscule, unless you have a truly horrendous laser.
If you're carrying a several gigaWatt laser rifle around in micro gravity then there are probably bigger problems to contend with.
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Post by Kuroneko »

Admiral Valdemar wrote:If you're carrying a several gigaWatt laser rifle around in micro gravity then there are probably bigger problems to contend with.
Precisely why I said it is very miniscule. I only picked a gigawatt because it comes to almost precisely three-quarters of a pound, a rather easy number to visualize. You can use 7.499e-10lb per watt if you prefer.
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Post by SirNitram »

Lasers in space, always. Superior efficiency, speed, range, and recoil. The only way to beat them is to reach levels of tech where missiles can cross lightsecond ranges effectively.

Nuclear/Antimatter missiles against ground targets. What? I'm supposed to be merciful?
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Post by His Divine Shadow »

Admiral Valdemar wrote:Yes, it would.
Said weapon would have to be very poorly designed from the ground up then.
A fast laser pulse should make your flesh fucking explode as if you've been hit with a large callibre bullet, and then another rapid pulse comes making your innards explode and thats FATALITY
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Post by His Divine Shadow »

Admiral Valdemar wrote:
Captain Jack wrote:I see: a Powerful laser can be very nasty. What we need now is a good portable power supply.
Polonium-210 rod encased in a 10/89/1% mixture of CO2, N and He, produces lethal blasts of 1.9kW to a target upto 1.5km away. Lasts around 60 days before nuclear decay reduces power significantly.
I want a laser weapon powered with that, or maybe a MASER based one.
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Post by His Divine Shadow »

Sea Skimmer wrote:
SyntaxVorlon wrote:There's no kickback for a laser.
If by that you mean recoil, then you are wrong. Lasers do have recoil.
Yeah but we're talking MJ range pulses before it'll even be close to that of a modern firearm.
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Post by His Divine Shadow »

Kuroneko wrote:
Admiral Valdemar wrote:In Zero G I would highly reccomend you use a low recoil weapon like a recoilless rifle or laser lest you want to become space debris.
How much recoil does a recoilless rifle actually have? IIRC it uses venting from the back to cancel out the force from the projectile, but that it could cancel out the force to negligible levels seems much too optimistic to me.

By my calculation, a laser has recoil of 0.750 pounds per gigawatt of the beam. That's quite miniscule, unless you have a truly horrendous laser.
Pimp mode, this is just what my calculator is for:
http://www.hisdivineshadow.com/misc/massless.asp
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Post by His Divine Shadow »

Hey wait a minute, stavatti, isn't that the joke company that talks about fighting aliens?
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Post by Kuroneko »

His Divine Shadow wrote:
Kuroneko wrote:By my calculation, a laser has recoil of 0.750 pounds per gigawatt of the beam. That's quite miniscule, unless you have a truly horrendous laser.
Pimp mode, this is just what my calculator is for:
http://www.hisdivineshadow.com/misc/massless.asp
Nice, though with such a simple calculation (Power(W)/Lighspeed(c) = Force(N)), a script isn't truly necessary. A script that calculates velocity from kinetic energy and vice versa for particular particles would be nice, since it is annoying to look up their masses, not to mention a fairly ugly formula. E.g., v = sqrt(1-1/(K/(mc^2)+1)^2); a proton has mass 938.28 MeV/c^2 and electron 0.5100 MeV/c^2 (so K would obviously be in MeV also). Actually, the recoil of a particle beam would be even better.
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Post by His Divine Shadow »

Kuroneko wrote:Nice, though with such a simple calculation (Power(W)/Lighspeed(c) = Force(N)), a script isn't truly necessary
But easy, and so I made it, because I could.

And I believe my formula is (Energy(J)/Lighspeed(c) = Force(kg·m/s))

Isn't one of these wrong then? Since I believe kg·m/s and newtons are different, 1kg·m/s I think is 9.8 Newtons
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Post by Admiral Valdemar »

His Divine Shadow wrote:Hey wait a minute, stavatti, isn't that the joke company that talks about fighting aliens?
Well done. Image
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Post by His Divine Shadow »

Admiral Valdemar wrote:
His Divine Shadow wrote:Hey wait a minute, stavatti, isn't that the joke company that talks about fighting aliens?
Well done. Image
You sir are a real Robert Scott Andersson
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Post by Admiral Valdemar »

His Divine Shadow wrote:
Admiral Valdemar wrote:
His Divine Shadow wrote:Hey wait a minute, stavatti, isn't that the joke company that talks about fighting aliens?
Well done. Image
You sir are a real Robert Scott Andersson
That's quite a big insult for such a small prank. If it's any consolation, it fooled me at first too.

I want a real TIS-1 though. :D
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Post by Kuroneko »

His Divine Shadow wrote:And I believe my formula is (Energy(J)/Lighspeed(c) = Force(kg·m/s))
Isn't one of these wrong then? Since I believe kg·m/s and newtons are different, 1kg·m/s I think is 9.8 Newtons
Yes, your formula is correct in as much as it gives the result in kg·m/s. That, however, is not a measure of force, but a measure of momentum. Hence, your calculation is correct in being a 'momentum calculator', which is what you advertise it as on the page. However, recall that F = ma, hence force is in kg·m/s^2, acceleration being in meters per second per second.

The condition that that laser puts out the given amount of energy in a one second pulse is therefore superfluous. All that's important for momentum is the energy of the pulse, not its duration.

Edit: I almost forgot: 1G (Earth gravity) is the acceleration of 9.8 N/kg, i.e. 9.8 m/s^2, which is where you're getting this number from.
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