Would a laser gun recoil? - Polidicks

[QUOTE=Xen Tricks;22089581]Actually, as the novelization of A New Hope (I believe) pointed out, most every starfighters is equipped with a virtual sound system, in which the ship's various sensors work out a sort of sound space outside of the starfighter which is then fed back to the pilot to give them a better sense of position in the battle. From that, one could assume that the sounds we hear in the movies in outer space are merely the synthesized sounds of battle from inside of the fighter's cockpit.[/QUOTE] Now they are just throwing random shit to justify scientific inaccuracies. Someone should tell them that it's okay because it's just a space opera, Jesus Christ, not something to be taken seriously (lol tell that to the fans)

You need to understand how light is emitted from a laser first, It won't actually push back and if a laser was that powerful, it would destroy the mass in front of it and no recoil would take place.

[QUOTE=Snoops;22084247]Yes, it would have recoil[/QUOTE] I don't agree with that, its energy not a physical projectile. so there for no recoil

[QUOTE=GrimWeafer;22092121]I don't agree with that, its energy not a physical projectile. so there for no recoil[/QUOTE] It has momentum

[QUOTE=Mr Donovan;22087276]Even someone who only paid attention to Star Wars as a little kid should know that the "lasers" in Star Wars actually fired bolts of pressurized plasma.[/QUOTE] Correct, they never once mention any of the blaster weapons as laser weapons. Also I would suspect that the plasma is contained within some form of magnetic field, to stop the plasma dispersing in an atmosphere.

I like laser guns.

[QUOTE=Eudoxia;22084224]Actually you can, if you are standing in front. If you can see the laser on it's path then it's a shitty laser because of dispersion. Or because there are particles there reflecting stuff,[/QUOTE] seeing it on its path is the cool part

I have no knowhow on this but i'd say not. Or at least not noticeable. Lasers are a bad idea in space anyway. But i guess that's off-topic.

[QUOTE=GrimWeafer;22092121]I don't agree with that, its energy not a physical projectile. so there for no recoil[/QUOTE] Light is a wave AND a particle.

Light shouldn't create recoil.

I like this thread. :synpa:

A laser beam with the same energy as a bullet? Jesus christ.

I'm gonna ask my biology teacher this. She has a "wonder box" where students can submit science related questions for her to answer. I'm gonna laugh if she says there would be no recoil.

Whoever wrote this made a strange assumption: recoil isn't related to the force, it's related to the momentum. He got the right answer, that the recoil would be several orders of magnitude lower, then changed his mind and pretended that force is more closely related to the recoil. If a laser gun weighed 1kg, it would be moving about half a millionth of a meter per second at the end of the blast, so slow as to be unnoticeable to anyone holding the gun - a breeze would be more significant. However, a sustained blast for about a 25 milliseconds (using his numbers) would produce significant recoil, something he didn't seem to consider.

[QUOTE=Thy Reaper;22095427]Whoever wrote this made a strange assumption: recoil isn't related to the force, it's related to the momentum. He got the right answer, that the recoil would be several orders of magnitude lower, then changed his mind and pretended that force is more closely related to the recoil. If a laser gun weighed 1kg, it would be moving about half a millionth of a meter per second at the end of the blast, so slow as to be unnoticeable to anyone holding the gun - a breeze would be more significant. However, a sustained blast for about a 25 milliseconds (using his numbers) would produce significant recoil, something he didn't seem to consider.[/QUOTE] What are the equations you used, and sauce if possible.

[QUOTE=QuadCoreGman;22095473]What are the equations you used, and sauce if possible.[/QUOTE] Momentum = Force * Time Momentum = Mass * Velocity Source for what?

This isn't news.

[QUOTE=Thy Reaper;22095502][B]Impulse[/B] = Force * Time Momentum = Mass * Velocity Source for what?[/QUOTE] Fixed. Also, I meant the numbers that you used.

[QUOTE=QuadCoreGman;22095555]Fixed. Also, I meant the numbers that you used.[/QUOTE] Yeah, meant Delta Momentum. I took them from the OP.

[QUOTE=Thy Reaper;22095576]Yeah, meant Delta Momentum. I took them from the OP.[/QUOTE] Rated self bad reading.

Uhh . . .

[B]If[/B] it has/had recoil it would be so incredibly small you wouldn't know it was there.

[QUOTE=Str4t0s;22084169]Fun fact, lasers in star wars are not realistic, because you cannot see lasers in space.[/QUOTE] I thought guns in Star Wars fired super heated gas?

I think the more appropriate question is, would a recoil gun laser?

The photons of a "Light Amplification by Stimulated Emission of Radiation" is not emitted by a "force" hitting the "photons" so no. The emited photon just results in electrons being in a lower energy level and that energy is just dependent on the quantum number n, aka the allowed solve of the radial compund of the wavefunction, you can interpret this as the "radius". So no.

This thread is full of people coming in and saying "light has no mass therefore no", and then being corrected by people who know physics. I don't even know who is right anymore.

[quote] For comparison, the momentum (p=mv) of a .22 bullet is .83 kg*m/s. The momentum of a laser gun is 2 million times less than the momentum of a .22. But is momentum all we should consider? I suspect the 'kick' we feel on the recoil is directly related to the force that the gun exerts on the holder. This means that instead of momentum we need to consider impulse, momentum per time. We estimate the time it takes to fire a .22 is ~.1s, so the force delivered 8.3 N. Let's estimate the time it takes a laser gun to fire. Unfortunately, not having a laser gun to fire (feel free to send me one, dear readers), we're more or less going to have to guess at the firing time. Most movies with laser guns show pulses of light (which, incidentally would move so fast we wouldn't see them) on the order of a meter or two long. Given the speed of light, this would give a firing time of ~30 nanoseconds. This would give a force delivered of 15 N. This is close to what we estimated or a .22. So, if movies are to be believed (and really, why wouldn't we believe them?), it seems like laser guns may well have recoil.[/quote] I = Δp I ≠ Δp/t I = Ft The impulse caused by the laser is the change of momentum. If you divide it by time, you get the force. The recoil we feel depends on both the force and the time time it affects. If the time is really short, ie. in the case of a gun, we won't notice it until after the force has already accelerated the gun. After that, what only matters is the impulse. The force gave the gun an acceleration, which caused its velocity to change. That change in velocity, multiplied by mass, is the impulse, and we need to counter it. The smaller the impulse is, the less we'll feel recoil. The best way to describe recoil is impulse, not force. You can accelerate something with a force of 10^6 N for 10^-6 seconds and counteract the recoil with just 1 N for 1 second. Take a weight of 100 grams and hold it in your hand for 1 second. That's the recoil. The recoil doesn't transmit to your entire body instantly. It's dampened by first the deformation of the gun and then the deformation of your hand (flesh is soft). The gun can also be made so that it distributes the recoil even more evenly with some kind of a spring system. A recoil of 4.5 * 10^-7 Ns can't even be felt.

I never knew until now that many scientists frequent Facepunch.

[QUOTE=Mattz333;22092373]Correct, they never once mention any of the blaster weapons as laser weapons. Also I would suspect that the plasma is contained within some form of magnetic field, to stop the plasma dispersing in an atmosphere.[/QUOTE] The blasters are miniture mass drivers probably.

[QUOTE=ThePuska;22098391]I = ΔM I ≠ ΔM/t I = Ft The impulse caused by the laser is the change of momentum. If you divide it by time, you get the force. The recoil we feel depends on both the force and the time time it affects. If the time is really short, ie. in the case of a gun, we won't notice it until after the force has already accelerated the gun. After that, what only matters is the impulse. The force gave the gun an acceleration, which caused its velocity to change. That change in velocity, multiplied by mass, is the impulse, and we need to counter it. The smaller the impulse is, the less we'll feel recoil. The best way to describe recoil is impulse, not force. You can accelerate something with a force of 10^6 N for 10^-6 seconds and counteract the recoil with just 1 N for 1 second. Take a weight of 100 grams and hold it in your hand for 1 second. That's the recoil. The recoil doesn't transmit to your entire body instantly. It's dampened by first the deformation of the gun and then the deformation of your hand (flesh is soft). The gun can also be made so that it distributes the recoil even more evenly with some kind of a spring system. A recoil of 4.5 * 10^-7 Ns can't even be felt.[/QUOTE] Oh my god there IS NO RECOIL AS THE PHOTONS AREN'T PROPELLED BY A VECTORED FORCE.