What is Bullet: Definition and 650 Discussions

A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. The term is from Middle French, originating as the diminutive of the word boulle (boullet), which means "small ball". Bullets are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax. Bullets are made in various shapes and constructions (depending on the intended applications), including specialized functions such as hunting, target shooting, training and combat. bullets are often tapered, making them more aerodynamic. Bullet sizes are expressed by their weights and diameters (referred to as "calibers") in both imperial and metric measurement systems. For example: 55 grain .223 caliber bullets are of the same weight and caliber as 3.56 gram 5.56mm caliber bullets. Bullets do not normally contain explosives (see Incendiary ammunition and Exploding bullet), but strike or damage the intended target by transferring kinetic energy upon impact and penetration (see terminal ballistics).
Bullets are available singly (as in muzzle-loading and cap and ball firearms), but are more often packaged with propellant as cartridges ("rounds" of ammunition). Bullets are components of paper cartridges, or (much more commonly) in the form of metallic cartridges. Although the word bullet is often used in colloquial language to refer to a cartridge round, a bullet is not a cartridge but rather a component of one. A cartridge is a combination package of the bullet (i.e., the projectile), the case (which holds everything together), the propellant (which provides the majority of the energy to launch the projectile) and the primer (which ignites the propellant). This use of the term bullet (when intending to describe a cartridge) often leads to confusion when a cartridge, and all its components, are specifically referred to. The cartridges, in turn, may be held in a magazine or a belt (for rapid-fire weapons).
The bullets used in many cartridges are fired at muzzle velocities faster than the speed of sound—about 343 metres per second (1,130 ft/s) in dry air at 20 °C (68 °F)—and thus can travel a substantial distance to a target before a nearby observer hears the sound of the shot. The sound of gunfire (i.e. the "muzzle report") is often accompanied with a loud bullwhip-like crack as the supersonic bullet pierces through the air creating a sonic boom. Bullet speeds at various stages of flight depend on intrinsic factors such as sectional density, aerodynamic profile and ballistic coefficient, and extrinsic factors such as barometric pressure, humidity, air temperature and wind speed. Subsonic cartridges fire bullets slower than the speed of sound, so there are no sonic booms. This means that a subsonic cartridge, such as .45 ACP, can be substantially quieter than a supersonic cartridge, such as the .223 Remington, even without the use of a suppressor.Bullets shot by firearms can be used for target practice or to injure or kill animals, or people. Death can be by blood loss or damage to vital organs, or even asphyxiation if blood enters the lungs. Bullets are not the only projectiles shot from firearm-like equipment: BBs are shot from BB guns, airsoft pellets are shot by airsoft guns, paintballs are shot by paintball markers, and small rocks can be hurtled from slingshots. There are also flare guns, potato guns (and spud guns), rubber bullets, tasers, bean bag rounds, grenade launchers, flash bangs, tear gas, RPGs, and missile launchers.

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  1. A

    Momentum and Impulse of a bullet

    Homework Statement This is a two part question. Kim holds a 2.0kg air rifle loosely and fires a bullet of mass 1.0g. The muzzle velocity of the bullet is 150m/s. What is the recoil speed of the rifle? ^ I got -.075m/s Part Two: If Kim in the previous questions holds the rifle tightly...
  2. R

    Does a bullet fired with a clockwise spin travel faster or slower

    or the same speed than if it had a counter-clockwise spin?
  3. C

    A bullet from speeding to full stop.

    Homework Statement A bullet (mass 15 g) moving at a speed of 425 m/s is brought to a stop in 3.5 cm in a block of wood. Homework Equations Find the force on the bullet, assuming that it is constant. The Attempt at a Solution what law should we use? 0 - 1/2*m*V^2 = m*g*0.035 + F*0.035 ?
  4. A

    Calculating muzzle speed from bullet drop without a chronograph

    Forgive my naivety. I used to know math, but have sort-a fallen off the bicycle some 30 years ago. I hope I don't go all ballistically ignorant. I have a problem trying to calculate muzzle velocity for pellet rifles. Specifically, I assume there is a way to do it without a chronograph and come...
  5. J

    Calculating Speed of Lead Bullet on Steel Sheet

    Homework Statement A lead bullet at 320K is stopped by a sheet of steel so that it reaches its melting point of 600K and completely melts If 80% of the k.e of the bullet is converted into internal energy calculate the speed with which the bullet hits the stee sheet. Homework Equations...
  6. S

    Bullet hits wood block, slides, hits ideal spring: cons. of energy/momentum

    Homework Statement A 50g bullet traveling horizontally at 200 m/s embeds itself in a much more massive wooden block initially at rest on a horizontal surface ( \muk = 0.10). The block then slides 1.2 m toward an ideal spring and collides with it. The block compresses the spring (k=600.0 N/m) a...
  7. T

    Finding the speed of a disk after being hit by a bullet.

    Homework Statement A .01kg bullet traveling at 800m/s hits a disk with a radius of R=.1m at R/2 and leaves with a speed of 400m/s. what is the angular speed of the disk right after? (omega) Homework Equations conservation of angular momentum Inertia for a disk The Attempt at...
  8. H

    Solve for Bullet Speed Before Hitting Block: A 47.00g Bullet

    Homework Statement A 47.00 g bullet hits and becomes embedded in a 5.10 kg wooden block which is hanging from a 2.50 m long string. This causes the block to swing through an arc of 23.50o. What was the speed of the bullet before it hit the block? mb = 0.047kg mw = 510kg r = 2.50 theta =...
  9. B

    Angular momentum: bullet through block with rod and pivot

    7. 0/10 points All Submissions Notes Question: SerPSE8 11.P.037. Question part Points Submissions 1 2 0/5 0/5 4/100 2/100 Total 0/10 A wooden block of mass M resting on a frictionless, horizontal surface is attached to a rigid rod of length script i and of negligible mass. The rod...
  10. A

    Bullet Hitting Wood the Spring, check of solution

    Homework Statement A 50g bullet traveling horizontally at 200 m/s embeds itself in a wooden block, initially at rest, on a horizontal surface (μk=0.1). The block slides 1.2m toward a spring and collides with it. The block compresses the spring (k=600 N/m) by 20 cm. Find the mass of the wood...
  11. K

    Entropy change of a bullet hitting water

    Homework Statement Calculate the change in entropy when a lead bullet of mass 10 grams traveling at 500 m/s hits a very large volume of water. Assume that the bullet was initially at 150 degrees Celsius and the water was at 25 degrees Celsius. Homework Equations K=\frac{1}{2}\,{{\it...
  12. X

    Solving Force of 17g Bullet Accelerated in Rifle Barrel

    Homework Statement A 17 g bullet is accelerated in a rifle barrel 103 cm long to a speed of 392 m/s. Use the work-energy theorem to find the average force exerted on the bullet while it is being accelerated. Answer in units of N. Homework Equations The Attempt at a Solution...
  13. S

    Bullet and Can Collision: Determining Bullet Speed After Impact

    Homework Statement A 7g bullet moving horizontally at 200 m/s strikes and passes through a 150 g tin can sitting on a post. Just after impact, the can has a horizontal speed of 180 cm/s. What the bullet's speed after leaving the can? ANSWER = 161 m/s Homework Equations 7g = .007 kg 150 g...
  14. B

    Probability density for bullet hitting a target

    The probability density for bullet hitting a target is given by f(x,y)=C.Exp(-(x^2+y^2)/2sigma square. What is the value of C. Sketch the curves of constant density in the XY plane. What kind of curve are they? What are the most probable hitting areas?
  15. R

    Angular momentum of a bullet

    Homework Statement A uniform stick 1.3 m long with a total mass of 260 g is pivoted at its center. A 3.6 g bullet is shot through the stick midway between the pivot and one end. The bullet approaches at 250 m/s and leaves at 140 m/s. With what angular speed is the stick spinning after the...
  16. P

    Bullet in a block hitting a spring

    Homework Statement An 8-g bullet is shot into a 4.0-kg block, at rest on a frictionless horizontal surface. The bullet remains lodged in the block. The block moves into a spring and compresses it by 5.0 cm. The force constant of the spring is 2200 N/m. In the figure, the initial velocity of...
  17. D

    Ballistic Pendulum speed of a bullet

    Homework Statement The speed of a rifle bullet may be measured by means of a ballistic pendulum in the following way. The bullet, of known mass m and unknown speed v, embeds itself in a stationary wooden block of mass M, suspended as a pen- dulum of length L. This sets the block to...
  18. C

    Bullet strikes block on friction surface

    Homework Statement A 26.2 g bullet is fired horizontally into a 1.32 kg wooden block resting on a horizon- tal surface (μ = 0.173). The bullet goes through the block and comes out with a speed of 298 m/s. If the block travels 3.01 m before coming to rest, what was the initial speed of...
  19. C

    Bullet colliding into block, sliding across surface with friciton

    Homework Statement A 125. gram bullet traveling at 300. m/s strikes and sticks into a stationary 5.00 kg block of wood. The combined bullet + wood initially slides on a horizontal frictionless surface until they encounter a second horizontal surface with a coefficient of kinetic friction...
  20. M

    How does the movement of a block affect the penetration depth of a bullet?

    Homework Statement Problem from the book: "A 7 gram bullet, when fired from a gun into a 1 kg block of wood held by a vise, penetrates the block to a depth of 8 cm. This block of wood is next placed on a frictionless horizontal surface, and a second 7 gram bullet is fired from the gun into the...
  21. M

    Bullet and Pendulum Problem

    Homework Statement diagram: http://goo.gl/uPl0 Part A A bullet of mass 0.0175 kg and speed vb passes completely through a pendulum bob of mass 1.3 kg. The bullet emerges with a speed 0.5vb. The pendulum bob is suspended by a stiff rod of length 1.1 m and negligible mass. The acceleration of...
  22. H

    What is the speed of the block after the collision?

    Homework Statement When a bullet strikes a block of wood originally at rest, the bullet becomes embedded into the wood block which travels 1.70 m after the collision. If the mass of the bullet is 5.26 g and the mass of the block is 2.40 kg, what is the speed of the block immediately after the...
  23. H

    Calculating the Speed of a Block After a Bullet Collision

    Homework Statement When a bullet strikes a block of wood originally at rest, the bullet becomes embedded into the wood block which travels 1.70 m after the collision. If the mass of the bullet is 5.26 g and the mass of the block is 2.40 kg, what is the speed of the block immediately after the...
  24. JJBladester

    Bullet velocity using impulse-momentum

    Homework Statement The following mathematical model was suggested for the variation in pressure inside the 10-mm-diameter barrel of a rifle as a 25-g bullet was fired: p(t)=(950MPa)e^{-t/(0.16ms)} where t is expressed in ms. Knowing that it took 1.44 ms for the bullet to travel the length...
  25. O

    Solving Mass from 2 Forces & Force of Impacting Bullet

    Part 1 1. The only two forces acting on a body have magnitudes of 20 N and 42 N and directions that differ by 60°. The resulting acceleration has a magnitude of 20 m/s2. What is the mass of the body?2. F=ma3. I am not sure how to solve this because I'm used to being able to use trig like cos...
  26. Q

    Maximizing the height of a bullet in cylindrical coordinates

    Homework Statement A gun can fire shells in any direction with the same speed v0. Ignoring air resistance and using cylindrical polar coordinates with the gun at the origin and z measure vertically up, show that the gun can hit any object inside the surface z = \frac{v_{0}^{2}}{2g} -...
  27. M

    2 questions: Force of bullet and car

    Homework Statement (1)A 5g bullet leaves the muzzle of a rifle with a speed of v=320m/s. what force (assumed constant) is exerted on the bullet while it is traveling down the 0.82m-long barrel of the rifle? (2)Two forces are applied to a car in an effort to move it. what is the resultant of...
  28. T

    How Does Wood Resistance Affect Bullet Penetration and Stoppage Time?

    Homework Statement A rifle with a barrel length of 56 cm fires a 10 g bullet with a horizontal speed of 350 m/s. The bullet strikes a block of wood locked in position and penetrates to a depth of 13 cm. What resistive force (assumed to be constant) does the wood exert on the bullet...
  29. D

    Bullet Projectile motion Problem

    Today I had a question from a student that made me think. Maybe I am just over thinking this. We were discussing the independent nature of horizontal and vertical components of motion. This was done through shooting a dart gun. We came to the conclusion that (without air resistance) the...
  30. B

    Random questions: explain BB gun bullet dent in (regular) glass?

    Hi all, this has been bugging me so maybe you can help me out. In the front window of my house, there is a dent in the glass that looks somewhat similar to this: http://www.flickr.com/photos/guerra/2557095422/" However, there is not hole in the glass. But the shape of the dent is...
  31. S

    Kinematics in one dimension - hot air balloon and bullet

    Homework Statement A hot air balloon is ascending straight up at a constant speed of 8.10 m/s. When the balloon is 13.0 m above the ground, a gun fires a pellet straight up from ground level with an initial speed of 28.0 m/s. Along the paths of the balloon and the pellet, there are two...
  32. F

    A beam of light compared to bullet in gun

    If a train goes past an observer at 100km/hour and someone on the train fires a bullet from a gun in the direction the train is going at 700km/hour, then relative to an observer, that bullet will go past at 800km/hour. Einstein made a statement of the type that if a person on the train holds a...
  33. F

    How Does Angling a Steel Target Affect Bullet Deflection and Energy Absorption?

    Hello Mighty Ones! I know from an FBI study that a bullet shot at a 90 degree angle into a metal plate, the splatter from the bullet goes out at a 20 degree angle. The question is... is there a rule or something that says if I angle that 90 degrees to angle down X degrees will the...
  34. M

    Studying Conservation of Momentum in Shooting a Bullet

    Ok so I want to know if conservation of momentum can be applies in a case of shooting a bullet to the wall I am talking about in the x direction of course since gravity is an external force in the y direction so a let say I shoot a bullet in a straight angle to the wall so it has huge x...
  35. R

    Bullet hitting a block of wood

    Homework Statement A bullet leaves the muzzle of a rifle at an unknown velocity and strikes a wooden block that is suspended by a piece of string. If the block swings backwards to make an angle of 40 degrees, at what velocity must have the bullet been traveling when it struck the block? mass of...
  36. R

    What is the Role of Gyroscopic Inertia in Bullet Spin?

    I was wondering why a bullet spins. From what I read a spinning bullet shoots straighter, but I don't really understand why since the Magnus Effect would cause it to drift or does the gyroscopic inertia compensate for this? Also, does gyroscopic inertia cause the rotational axis to be stable...
  37. G

    Silly collision question; hit by turkey vs. hit by bullet

    Hi, everyone. Please help us work through a hypothetical situation that we came up with at work. We're chemists, not physicists, and none of us have had to do physics equations since undergrad. So, we're kind of hopeless without help. We were thinking about the following scenario. In the...
  38. T

    Momentum and Energy related Bullet Question

    A 5.00 g bullet is fired into a 6.00 kg block, which is suspended from a string 1.00 m long. The string deflects through an angle of 12.0°. How fast was the bullet moving?a Transitional KE = ½ mv2 Rotational KE = ½ I2 Elastic PE = ½k L 2 I'm not sure those are the right formulas...
  39. L

    Conservation of momentum of a bullet question

    Homework Statement A bullet is shot horizontally into a block suspended by two strings. The bullet remains embedded in the wood and the wood and bullet together suspend upward. a) Explain why the horizontal momentum of the bullet-wood system is conserved during the collision even though the...
  40. W

    Realistic bullet drop calculation

    Homework Statement A little while ago I made a thread about the drop of a bullet due to gravity on a bullet with a constant velocity. Constant velocity is unrealistic, so I am going for a little more realism here. I am doing this assuming that I have detailed information about distance...
  41. M

    Determine the initial speed of the bullet

    Homework Statement An 8.00 g bullet is fired into a 160 g block that is initially at rest at the edge of a table of 1.00 m height. The bullet remains in the block, and after the impact the block lands d = 2.2 m from the bottom of the table. Determine the initial speed of the bullet...
  42. P

    Lob vs. Bullet Pass: Initial Speed and Launch Angle Calculation

    the lob pass is thrown with an initial speed of 21.5 m/s and its time of flight is 2.97s. What is its launch angle? The bullet pass is thrown with a launch angle of 25 degrees. What is the initial speed of this pass? What is the time of fight of the bullet pass? what formulas and how is...
  43. M

    Bullet fired at a block of wood

    Homework Statement An 19-g bullet is shot vertically into an 5-kg block. The block lifts upward 5 mm. The bullet penetrates the block in a time interval of 0.001 s. Assume the force on the bullet is constant during penetration. The impulse on the block due to capture of the bullet is closest...
  44. L

    Calculating Final Temperature of Lead Bullet

    Homework Statement A 5 g lead bullet moving at 343 m/s is stopped in a block of wood. All of the kinetic energy goes into heat energy added to the bullet. The initial temperature of the bullet is 24 degrees C. What is the final temperature of the bullet in degrees C? (cPb = 0.128 kJ/kg . K...
  45. W

    Is my simplified bullet drop equation accurate for long-range shooting?

    Homework Statement I was wondering if you guys could see if my equation on bullet drop is correct. I know there are more factors than what I am presenting, but this is only a simplified version... The distance an object with 0 initial vertical velocity falls is d_{drop}=\frac{1}{2}gt^{2}...
  46. R

    Calculating Kinetic Energy & Average Force of a 1.35g Bullet

    Part 1.) 1.35g bullet leaves the barrel of the gun going 270m/s. What is its kinetic Energy? -I converted 1.35 g to kg = 0.00135g -I arrived with an answer of 49.2075 J Part 2.) If the length of the barrel of the gun described above is 35cm, find the average force...
  47. D

    Impact of a Bullet into a Block

    So I checked out the physics class I was taking on ratemyprofessor.com and John Ross was the guy who was teaching it. He had good reviews, so I figured I'll take his class. Well, a TA is teaching it, and I won't name the person, but he isn't really a teacher--even with his PhD in astrophysics...
  48. T

    Bullet trajectory; solving for required angle of elevation

    Homework Statement Bob is trying to hit a stationary target 146.00m downrange, his eyes are 1.8m above the ground, firing from a standing position. The muzzle velocity of the projectile is 382.524m/sec (1255 ft/sec), wind is negligible; at what firing angle must he fire to successfully hit the...
  49. J

    Why Doesn't a Bullet Tumble When Fired from a Rifled Barrel?

    Had a quick search, didn't find anything. So, we have been told on our course, that a spinning extended object will "re-align" itself such that it is spinning along a principle axis with the highest moment of inertia, such as to conserve angular momentum, but minimise rotational kinetic...
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