It appears we have yet another "Matrix-like" action fantasy violence-fest in the just-released movie Wanted starring James McAvoy, Angelina Jolie and Morgan Freeman. The curving-bullet scene we see in the trailer is fast becoming a topic of conversation in certain moviegoing circles (i.e. high-school kids). It appears that McAvoy applies a little "English" to the bullet with that fancy flip of the wrist. Now, clearly the scene is just silly fantasy –curving a bullet a couple of feet around a butchered pig does not conform to the physics of the known universe. However, the interesting question is whether or not it might be possible to manipulate the gun to impart any kind of curve at all.
Ballistics is a rather complicated topic. When a bullet is fired out of the barrel of a gun it can have a velocity of up to 1000 m/s and a rotation rate up to hundreds of thousands of rpm. It is immediately subjected to the downward pull of gravity, and a large air-drag force slowing the bullet down. While the rotation stabilizes the bullet by the same principle that a spinning gyroscope is hard to knock over (conservation of momentum), this same rotation can result in a small upward or downward force along with a sideways drift as a result of the Magnus force. The Magnus force is the same force that makes it possible to throw a wicked curveball—the result of air traveling at different speeds around each side of a rapidly spinning ball, thus creating a different air pressure on each side. Of all of these forces, gravity has the largest effect on the bullet's trajectory. Over a distance of a five or ten meters like that shown in Wanted's slaughterhouse scene, the combination of these forces would result in a deflection of a few millimeters— obviously not sufficient to clear Angelina (and the pig) and hit the target.
Acknowledging all of the above, the question that we still need to address is: Could we get any additional help from the wrist flip? Another millimeter? Anything? The answer is (not surprisingly): no, we could not. The reason is very simple and has to do with Newton's first law of motion. The implication in the scene is that the curving trajectory of the gun is somehow imparted to the bullet before it's released and the bullet continues to curve after it leaves the barrel of the gun. That's not the way bullet-firing works. It's a common first-year physics misconception, for example, that a ball rolling around a curved track will continue in a curved path after it leaves the track. It won't. The reason an object follows a curved trajectory is because there is a force pulling it into that trajectory—for instance, the walls of the track pushing on the ball. As soon as the forces stop acting, the object is going to continue in a straight line at a constant speed, according to Newton's first law. Try this at home: Attach a string to a ball and swing it in a horizontal circle just above the ground, and then release it. Notice the path it takes after you release it. It's a straight line. Same thing with the bullet after it leaves the gun.
Adam Weiner is the author of Don't Try This at Home! The Physics of Hollywood Movies.
Well, as a regualr movie go-er, I saw Wanted when it premiered in my city. Before going to the movie, I was biased to think that it was just another aimless/plotless story based on the matrix style. To my surprise, it was actually a good movie with a solid plot. It is really hard these days to come up with new "powers" to give main actors.
Now heading to the bullet being curved, I assume that there could be a way (and I am just imagining since I have no physics backgrous what so ever), to use sequenced magnets to try to curve the bullet (similar system as the magnetic traains use for propulsion). But, in the movie, there are supposingly no tricks used... simple "If someone told you that bullets only flew in a curved way, and you didn't know anything about bullets, you would believe bullets really do travel in a curving manner" (or something of the sort). Well if we use that same principle, then if you bring up a kid and tell him that humans can fly, will it be able to fly? The answer is NO.
Though it is not physically possible ... would it be possible to curve the bullet if your "wrist action" rotation speed was the same speed that the bullet left the gun
Well, then the other impossibility is getting your wrist to that speed. It becomes related to the time travel theorem, where one could achieve it if he could accelerate his body to that of light.
You do realize that a bullet travels nowhere near the speed of light, right? A bullet, according to this article, travels at almost Mach 3, but not the speed of sound. Although this does not diminish the practicality nor the possibility of moving one's limb at this speed, I just thought I'd provide the thought for the sake of fact checking.
Since we're pointing out people's mistakes here brettsmaname, you do realize that Mach 3 is actually three times the speed of sound. Just thought you would like to be informed. You know, for the sake of fact checking and all.
it's not actually imposible to curve a bullet its humanly imposible
it's not actually imposible to curve a bullet its humanly imposible
it's not actually imposible to curve a bullet its humanly imposible
to get a bullet to move horizontally (say around one actress) could be done by moving the gun horizontally across the body, of course the speed at which this would be done would have to be very great to have any measurable effect over great distance. And just like a curveball you would aim to the left or right and have it curve back in.
It comes down to two main points:
1. To deflect the trajectory of the bullet, there needs to be some sort of force applied to the bullet while it is in flight. The Magnus Force is one such factor (the same thing that makes curveballs curve) but has negligible effect on the bullet in real life (a few millimeters).
2. Screwing around with the GUN itself will NOT affect the bullet's path after it has left the gun.
It's a fun idea brought to life in a movie, but like so many things in movies, it isn't realistic at all.
Recently on the Discovery channel's show Mythbusters they busted a simular myth that you can stop or even alter a bullets path with magnets. They rigged a path of high powered magnets under the bullets path and than fired a bullet out of a 9mm pistol (Im not sure on the gun), point being the most that they altered the bullets path was 4 or 5 mm. Hardley enough to be considered a drastic change. So curving a bullet need it be with magnets or useing a calculated recoche it is nearly impossible to reproduce in the way the way that the movie does the bullet curve. Even if you do move the bullet enough to avoid someone it will be slim to no chance of putting the bullet back around on its initial course and still hit the target with the speed and rotation that the bullet is moving at.
My two cents:
Bullets have a rotational motion, which causes a bullet to "bend." Unfortunately for Hollywood, this bending does not occur at close distances. At ranges approaching and exceeding one mile, bullets will bend slightly. They bend enough that you cannot accurately plot them within a certain radius (a matter of inches).
But you never hear about 2-mile shots. Aside from having to arc your shot severely, the parabolic rotation of the bullet becomes so much that the grouping radius is now a matter of feet. In other words, EXTREME long-shots are near-impossible due to the "bending" of a bullet.
Now, for pistols, the limitations of the weapon (short barrel, less rifling, bullet dynamics) make it so that the accuracy and effective range come into question long before parabolic rotation ever does.
What this movie should've done to be more believable is issue the assassins guns that fire flat disks similar to a Frisbee, and then they would have all of the aerodynamic tricks of a Frisbee at their disposal.
There is a way humans can force a bullet into a curved trajectory thereby impacting a target blocked by an obstacle. Below are detailed steps that will produce a successful outcome every time.
1. Remove a bullet of any caliber or grain from its casing
2. Grip said bullet between thumb and forefinger
3. Walk with bullet-in-hand around obstacle
4. Throw bullet very quickly at target.
Note: If point 4 does not achieve penetration of target, load a new, unspent (fully assembled) cartridge into a firearm. Proceed to fire at target from new location.
the thing that most people dont realize is that the rotation of a bullet completely different than a baseball curve. the baseball has a 3/4 over the top rotation, with the rotation spinning forward.
The disc comment above would seem the only logical way to make this curve work because the rotation is the correct direction to get the shown curve. a bullet does not have the correct axis of rotation to give it the desired effect shown in the movie.
All that taken into account with a grain of salt cause it was a movie, that was a fun ride nonetheless.
With the right steering gear on the projectile, it might turn, but I doubt if aerodynamic forces would be enough to turn it very much. Also, pistols don't spin the bullet.
what about shaping the bullet in the way that air pressure will affect it to curl to one side? similar to the lift a plane gets.
what if the bullet didn't exist , could you bend it
of course you could , there wouldn't be anything to bend
bend in what relation?
would a jagged , or otherwise reformed surface of a bullet change it's trajectory , of course it would
but at what point , meaning speed or force or energy (whatever you wanna call it)
would the bullet cease to fall victim(muhahahaha, lol) to it's surface , and therefore it's trajectory
i don't know for sure but i would imagine ( i use that word lightly)
that at a certain speed , no matter the surface of the bullet , it would overcome all except gravity
by the way , the wicked curve ball example is slightly off , as to say , what if you could change the way a bullet is fired , because while it is the rotation of the ball that determines how much it moves (not how far , just to make my point) isn't or rather , can the way the ball is gripped (it's rotation) and the sufficient force and angle applied to release the ball determine how the ball moves , and therefore the way a bullet is fired (increased rotation) plus , per say the angle and the amount of force/energy applied would seem to make the bullet move more.
I don't know if it would bend meaning leaving one plane to another plane then returning that plane , but it definitely would move , to perhaps miss the target beyond just not shooting in the proposed direction..
blah blah blah i know the ball and the bullet aren't the same blah blah ugh i don't even feel like continuing but if i get response i will further elaborate , but until then
bigger bullet + reformed surface + different firing mechanism (rotation)
+ reduced or increased energy (depending on angle) =
ha! , there you have it , a bullet that bends , wherever you want it to
but remember , if laws determine how you can make the board , i will smash it creating a new science that determines what can't break the board
Some of the comments on this board are amazing, I can't help but chime in.
1 - For those of you that have studied physics or dynamics you know that an object in motion will continue in motion at constant speed AND DIRECTION unless acted upon by an external force. That means that right after the bullet has left the barrel, it will want to move in a straight line at constant speed (in a vacuum in space, more on that later).
2 - We live on earth and not in a vacuum in space therefore there are ALWAYS two forces acting upon any moving object. First you have gravity pulling the object toward the earths center, and second you have fluid (wind) resistance slowing the object.
3 - That being said, in a perfect environment (does not exist) a bullet will slow down and fall toward the center of the earth every time no matter what, end of story. However we do not live in a perfect environment and there is this stuff called wind that will cause a bullet to move to the side. Therefore, if you want to hit an object at a great distance, you need to account for gravity, decrease in speed, and wind. Not easy, try it.
4 - Any imperfections in a bullets geometry will change it's trajectory, but not in any way that is predictable, sorry.
5 - Every pistol, rifle, (and some shotguns designed for slug hunting) manufactured after the civil war have what is called rifling which induces spin into the bullet for better accuracy. So yes pistols "spin" the bullet.
So, if you want to slow a bullet down, curve it toward the ground, and in the direction of the wind, than you are in luck because it will happen every time no matter what!
That was a good movie but its action is nearly impossible to do in real life.
Actually you can bend a bullet in a manner similar to the movie. You just cant use the same axis they did.
As the article states the largest force acting on the bullet is that of gravity. This causes the bullet to fly in an arc.
So they could curve the bullet OVER the pig, just not around it. And it would be over a longer distance.. but at least it could be done.
Your are all thinking too small. Angelina Jolie may look thin, but really she weighs, say, about as much as the sun. So, she warps the fabric of space-time around her and the bullet bends. Simple relativity in action. Flicking the wrist is just a way to make Jolie feel better, since she is, well, a bit overweight (by about 1.988 X 10^30 kg).
An average person could not bend a bullet even in the movie. But we must remember that Wesley was extremely unique in that his heart rate was 400 bpm which allowed him to not only be present but extremely fast.
So that group of Assassins may have been aware of a new law that Newton never discovered since Newton wasn't an elite, genetically enhanced killer.
Nor are most physicists to the best of my knowledge.
So the fact that we can't duplicate the bullet bending is not because it's not possible but because we don't have the right person shooting the test gun to show us that a new law exists that we haven't previously seen in practice.
It reinforces that we need to have precise conditions to confirm or negate this theory. But where are we going to find a bunch of assassins who will participate in a study for a $10 honorarium?
Any projectile fired at Angela would be 'bent' by the combined mental fusion of her manager and support staff. They wouldn't want their golden swan to die!
As you can see in the movie, the bullets aren't just normal bullets but have a built in guidance system and curve molded into them, is it perhaps possible to curve a bullet hard enough to do stuff like in this movie?
Like they do with laser tracking bullets?
Wouldn't it be possible if you used heavier, circular bullets and removed the grooves in the barrel(like the old pistols) so you can cause the bullet to spin in different direction and cause it to curve?
Fact, The Magnus Effect makes any 'Ricocheting' bullet extremely unpredictable. Even to the point of defying gravity and wind effect on the projectiles 'newly re-aligned' trajectory.
You cannot apply "English" to a bullet as you can to a baseball or a ball when playing Pool. The author explained the reason and the Law such that that even a junior high school student could understand it. The second the bullet leaves a weapon , any weapon for that matter, being flicked in attempt to impart "English" onto the round it [the bullet]travels in a straight line as the weapon barrel is no longer applying a centripetal force to the round!
The majority of your comments have caused some of my brain cells to die as a result of my reading the incoherent stupidity you've collectively spewed onto the Interntet.
Really I have to believe that either the balance of you are either Internet Trolls or are in fact incapable of dressing yourselves.
Please for the love of whatever God or Gods you pray to please re-read the article, go take a introductory course, read the Wiki entry, or use the OCW project to learn and understand the basic principles of Physics or remain stupid it's your choice.
All you people just don't get it.....
Do not try and bend the bullet.
Instead, only try to realize the truth . . .
There is no bullet . . .
Then you will see that it is not the bullet that bends, it is only yourself