What is Gun: Definition and 311 Discussions

A gun is a ranged weapon designed to use a shooting tube (gun barrel) to launch typically solid projectiles, but can also project pressurized liquid (e.g. water guns/cannons, spray guns for painting or pressure washing, projected water disruptors, and technically also flamethrowers), gas (e.g. light-gas gun) or even charged particles (e.g. plasma gun). Solid projectiles may be free-flying (as with bullets and artillery shells) or tethered (as with Taser guns, spearguns and harpoon guns). A large-caliber gun is also referred to as a cannon.
The means of projectile propulsion vary according to designs, but are traditionally effected pneumatically by a high gas pressure contained within the barrel tube, produced either through the rapid exothermic combustion of propellants (as with firearms), or by mechanical compression (as with air guns). The high-pressure gas is introduced behind the projectile, pushing and accelerating it down the length of the tube, imparting sufficient launch velocity to sustain its further travel towards the target once the propelling gas ceases acting upon it after it exits the muzzle. Alternatively, new-concept linear motor weapons may employ an electromagnetic field to achieve acceleration, in which case the barrel may be substituted by guide rails (as in railguns) or wrapped with magnetic coils (as in coilguns).
The first devices identified as guns appeared in China from around CE 1000. By the 12th century, the technology was spreading through the rest of Asia, and into Europe by the 13th century.

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  1. revix

    I Why momentum is conserved when a gun fires? (conceptual question)

    I understand that conservation of motion comes from the action and reaction pairs of newton's third law. When it is triggered, two forces appear that cancel when analyzed as a system. My question is how is it that momentum is conserved if before the shot there was no force in the system and...
  2. M

    Why do we need to take the absolute value of charge in an electron gun?

    For part (a) of this problem, The solution is, However, why did they need to take the absolute value of the charge? I thought they could keep the original signs as shown below: Using energy conservation, the electric force dose internal work transferring electric potential energy into...
  3. amorphos_b

    Gun with a tachyon bullet paradox

    Gun with a tachyon bullet paradox if you had a device akin to some kind of ‘gun’, which created tachyons and the fired them, perhaps in a beam or some kind of ‘packet’, when they go faster than the speed of light would go back in time. Lets say the ‘bullet’ or beam, went out into the universe...
  4. rsc9421

    A Power consumed by electron gun

    First Assume the following basic circuit: I read in many textbooks that the electrons in the circuit are accelerated by the positive voltage and decelerated by the collisions, so the speed is constant. We also know that the circuit current is I = 10A so the power consumed is P = V * I = 100W...
  5. J3J33J333

    Why don't cars use something like a rail gun instead of combustion?

    Why don't cars use something like a rail gun instead of combustion to drive pistons?
  6. mopit_011

    B Air Gun Sighted at a Falling Target Demonstration

    So in class today, we were talking about how if you fire a bullet aimed at a falling target and release the target and the bullet at the exact same time, they will surely collide. I asked if air resistance (since it’s not a constant force) wouldn’t affect the collision and my teacher didn’t have...
  7. A

    Why Does the Filament Box in a CRT Electron Gun Have Multiple Pins?

    While messing around with old tv's I had a Panasonic sent the innards to recycling but at the factory kept some souvenirs , broke off the electron gun from the tube (that sweet swoosh sound when the air rushes to fill the vacuum). So long story short I know the basics of how an electron gun...
  8. I

    Very preliminary thoughts on a recoil reducing gun

    I'm a second-year student and I'm trying to increase my knowledge of physics and engineering by designing a gun capable of loading and shooting very hot loads and at the same time converting the recoil energy into something more useful and or more manageable. as we all know the recoil and...
  9. S

    Newton's 3rd law question -- A gun firing a bullet

    I'm confused by which forces should be equal to each other and what I solve for. How should I approach this problem?
  10. rcgldr

    I Rail gun - point of application of force?

    A rail gun exerts an electromagnetic force on a projectile. The only moving object is the projectile, so is the point of application of force moving? Update - For others reading this thread, after a re-think on this, for linear motion (as opposed to angular motion), the point of application of...
  11. SWKatzen

    Exploring Electron Gun Deflection: Causes and Resources for Understanding

    Hi, I was wondering if anybody knows why the plate in an electron gun is tilted with respect to the electron path? Or has any resources that I could read to better understand? Thanks.
  12. K

    Why Are Multi-Barreled Muzzleloaders Inaccurate Despite Aligned Barrels?

    I was watching this video where they’re shooting an old muzzleloaded ”machine gun” with a barrel for each shot. I’m surprised that it’s so inacurrate. Why does the bullets spread, when each barrel is pointing towards the same direction? I’ve seen muzzleloaders like the ”duck foot pistol” that...
  13. R

    B Gun Recoil: Will Wall Impact Momentum & Velocity?

    I know this is a basic question but it has me stumped. If a gun is the same weight as its bullet and the gun is free to move when fired the momentum and velocity of the gun and bullet will be the same but in opposite directions. If we put that gun up against an immovable wall and fire it will...
  14. S

    Which direction should you aim to shoot a fish using a laser gun

    If we use a spear or gun with bullet, then we should aim lower than the position where we see the fish because due to refraction, the apparent position of the fish in the lake will be higher (nearer to the surface) than the actual position of the fish. But if we use a laser gun, I think we...
  15. jamiebean

    Velocity of bullet fired from a gun

    I first calculated the velocity v: √2.8^2+6.3^2= 6.8942 then i used it as the final velocity, so final velocity=6.8942 and the initial velocity=0 acceleration=9.8 Then i substituted them into this equation: final velocity=initial velocity + accelerationxtime then time=0.703489843 hence i...
  16. J

    MHB Find the average force required to hold the gun in position

    A gun fires 6 bullets per second into a target. The mass of each bullet is 3g & the speed of 500 m/s. Find the average force required to hold the gun in position.
  17. Baran

    Newton's third law -- Calculate the recoil of a paintball gun

    I've been stuck on this for sometime now, and am unsure how to approach this question.
  18. T

    Projectile Motion — How far from the gun does the bullet land?

    I don't know how to link the x-component and y-component together.
  19. B

    Projectile Compresses a Spring Gun

    This is a common homework problem and I did find a post here that talks about it, but that post was closed to comments, so I am reproducing it to be able to ask a question. We are, apparently, according to solutions I have found, supposed to recognize that it is an inelastic collision, since...
  20. D

    Electron gun in a vacuum -- How hard of a vacuum is needed?

    how high does a vacuum need to be for electron gun to work? for example, will 1 pascal work, will 1 tenth of a pascal work? is there a minimum vacuum for a electron gun to work?
  21. berkeman

    Is this officer checking his radar gun calibration incorrectly?

    I was watching "Northwest Law" last night (a TV show that follows Fish & Game Rangers in the Northwest), and when I saw an officer checking the calibration of their radar gun before using it on an ATV trail, I was very confused by it. He held it so that the tuning fork vibrated orthogonally to...
  22. C

    Is Specific impulse indicative of performance as a gun propellant?

    Black powder has specific impulse of around 80s, while rocket candy has up to 130s of specific impulse. Does that mean I could replace the propellant in a BP cartridge with 80/130 of the weight in rocket candy and obtain the same performance in an idealized gun? (as in without considering...
  23. P

    Can Ion Thrusters with Continuous Iron Expulsion Power Interplanetary Probes?

    if one once of Iron was accelerated to 80% of the speed of light, could this be use of as a means of thrust for an interplanetary probe? where the probe has a continuous expulsion of Iron. and ignoring the need massive amount of power.
  24. chucrut

    Electron Gun Design - Can Positive Voltage Work?

    Hello, I have a question about electron guns. I have read a lot, and all designs use high NEGATIVE voltage (-1000v for example). Is possible to use high POSITIVE voltage like this drawing?. Or do you think it will not work this way? Considering that all the chamber walls are at ground voltage...
  25. Arman777

    Probability of A Winning a Duel with One Gun and One Bullet

    Problem: A and B decide to duel but, being poor, they have just one gun (a six-shot revolver) and only one bullet. Being dumb, as well, this does not deter them and they agree to "duel" as follows: They will insert the lone bullet into the gun's cylinder, A will then spin the cylinder and shoot...
  26. R

    Electron Gun diffraction and undeflected spot diameter

    Hi I am doing an electron gun diffraction right now and I wonder why the angle below is 2 phi. What I think about it that it's actually the results of two waves one is shown below and the other is a wave with the same accident angle but negative "those two rays will be symmetric around the...
  27. K

    AP Physics C Momentum Problem: A dart launched horizonally by a spring gun

    Homework Statement A boy launches a 20 g dart horizontally by a spring gun from a balcony 45 m above the ground. The dart lands 15 m away from the balcony. If the length of the gun’s barrel is 10 cm, what is the average horizontal force applied by the spring?(A) 1.0N (B) 2.0 N (C) 2.5 N (D) 5. N...
  28. Javier Lopez

    I Stopping power for a proton ion gun through a Boron-11 sheet 1mm thick

    Hello, I need the stopping power for a proton ion gun through Boron-11 sheet 1mm thick. I have the following table obtained from here: https://www-nds.iaea.org/stopping/stopping_hydr.html Where the unit is in 1-15*eV*cm2/atom: Then I calculated for 600keV protons at table 5.1eV*cm2/atom. I...
  29. DracoMalfoy

    Conservation of Energy: Spring PE: Toy gun on spring

    Homework Statement A toy gun is pointed toward the sky. A Styrofoam ball of mass 10g is at rest against a spring compressed 2cm. The spring is released causing the ball to move upward through the air to a max height of 1m. The air exerts a frictional force of 0.35N on the ball. What is the...
  30. E

    China Develops Laser Gun Like Star Wars: Burns Through Skin

    China develops new laser gun similar to Star Wars. It can burn through skin to produce immense agony. Here...
  31. R

    A Calculating air gun energy vs PSI & bore diameter

    So I'm trying to figure out what kind of energy that I can expect out of a few different setups. Here are the barrel bore diameters. .224 .308 .5 .77 The barrels are usually rifles and some projectiles are full size (size of bore) while others use sabot's where a .224 or .308 can be shot...
  32. S

    Newton's laws of motion: A gun firing bullets....

    Homework Statement A gun fires bullets each of mass 1g with velocity of 10m/s by exerting a constant force of 5 g weight. Find the number of bullets fired per second (take g=10 m/s2). Homework Equations F=ma M1U1 + M2U2 = M1V1 + M2V2 (conservation of linear momentum) The Attempt at a...
  33. J

    B Electron Gun for a Grade 9 Physics Project?

    I am in grade 9 in the IB curriculum and next year I have to do something called a "Personal Project" where I have to make something and explain why I did it. I would like to recreate the double slit experiment. However, I have to obtain a electron gun and they are quite hard to come across. So...
  34. A

    Using an IR Thermal Gun to check for steam passing valves

    Greetings I am asking about the reliability of using a thermal gun to check if there is passing downstream the valve. The fluid is either steam or air. Wouldn’t the pressure and temperature drop sharply downstream the valve if it is closed but passing ? again I am talking about air or steam...
  35. L

    I Can a Gravitational 'Gun' Accelerate Objects?

    Hello, Special arrangements of charged material can be used to accelerate charged objects or particles, e.g. a cathode ray tube. I am just wondering if it would be somehow possible, in principle if not in practice, to accelerate objects with gravitational force using special arrangements of...
  36. R

    Magnetic Force Applied to An Object @ d (0,n) (Rail gun on Mars)

    So long story short, I'm trying to write a scientifically accurate short story/animation thing and it revolves around a mass driver: it's a giant and deep hole on Mars with a magnet on the bottom or sides or something and fires packets of objects to Earth at breathtaking speeds (4.66 million...
  37. C

    Projectile Kinetic Energy and Recoil in Spring Gun Experiment

    Homework Statement A projectile of mass M1 is fired horizontally from a spring gun that is initially at rest on a frictionless surface. The combined mass of the gun and projectile is M2. If the kinetic energy of the projectile after firing is K, the gun will recoil with a kinetic energy equal...
  38. Z

    I Drone Gun: A Revolutionary Weapon Against Rogue Drones

    A company named Drone Shield has developed a 'Drone Gun', which is capable of jamming a drone from up to 1.2 miles (approx. 2 km) away...
  39. M

    What alternatives to traditional guns are available for self-defense?

    Hi, I plan to buy a gun for general self or home defense. So many people own guns and I don't even have one. But is there any new guns that are not based on Newtonian bullets or projectile? For example. What is the smallest plasma or particle beam or laser guns. What are currently available...
  40. S

    Can a bullet hit someone while free falling?

    If two people are free falling from the sky at the same (high) speed, at the same altitude, but about 20 meters away from each other, and one of them has a gun and tries to shot the other, do they aim directly at the other person so they get a hit (because the bullet would also be falling), or...
  41. donaldparida

    Bullet trajectory: Aiming a gun

    Homework Statement : [/B]A person aims a gun at a bird from a point at a horizontal distance of 100m. If the gun can impart a speed of 500m/s to the bullet , then above what height of the bird he should aim his gun to hit it ? Homework Equations : [/B] H_{max}=\frac{u^2\sin^2\theta}{2g}...
  42. A

    How is momentum conserved in a Gauss Gun?

    Homework Statement So for those who aren't familiar with the Gauss Gun here is a video demonstrating its function: As you can see in the video, a steel ball is rolled towards a sequence of magnets and other steel balls and as the incoming ball strikes the magnet, the ball on the other end...
  43. P

    Ray gun from call of duty zombie?

    Can a ray gun be created? What would it fire? plasma? I know that the dimendion of the ray gun are too short for what am i going to say, but i want to ask if aside this problem this could work: I thought that maybe the things that you put in the ray gun to charge it are batteries, and that the...
  44. D

    Potential energy in Gauss' gun

    Homework Statement For my extended essay as part of the IB, I am investigating the effect of changing the distance and the number of stationary ball bearings in a Gaussian gun. I was hoping to look at the energy transfer during each stage of magnets and therefore calculate the efficiency...
  45. B

    Gun sound -- frequency analysis

    Small caliber guns have higher magnitude at higher frequencies and larger caliber guns have higher magnitude at lower frequencies. is this true ? because I am not see this in my test: that is the fft of a 9MM gun, As one can see there are low magnitudes at low frequencies and higher...
  46. B

    How can you identify the type of gun by the sound it makes?

    how can you identify the type of gun by the sound it makes ? Like if you had a recording of a gun shot but you Can't see the gun and you can find the bullet.
  47. R

    Solve Spring Gun Problem: Recoil Speed Calculation

    Homework Statement A mechanical gun of mass M(g) uses a spring to shoot a bullet of mass M(b). The energy of the compressed spring before firing is E. Assuming the gun is at rest before firing, what is the recoil speed of the gun immediately after it shoots the bullet? Homework Equations...
  48. R

    Dynamics: Cannon ball and the moving gun

    https://postimg.org/image/z96a0jn8b/ https://postimg.org/image/z96a0jn8b/ link to image (bcs the feature doesn't work): https://postimg.org/image/z96a0jn8b/ 1. Homework Statement A cannon (mass m_c) is standing on the ground before it fires a cannon ball (mass m_b). At the time t_0=0. the...
  49. D

    Rail Gun Problem: Force & Friction Analysis

    Homework Statement Homework Equations F_f = Nu F_B - IL x B The Attempt at a Solution [/B] Using the hint "The rod will begin to move when the force of friction is equal to the force due to the magnetic field." I was able to get the answer But I don't understand why it is that way. In...
  50. Alexander Stroborg

    Can a 400V 2200µF capacitor propel 0.5g through a rail gun?

    I am planning to conduct an academic experiment involving an electromagnetic projectile. I originally planned to build a rail gun powered by a 400V 2200µF capacitor, I've read a lot of discussions that say rail guns require a tremendous amount of current. Is this capacitor sufficient to propel...