[I did see that this was answered a few years ago but the answer was a little too unscientific] I’m watching the movie and decided to Google it. All the answers are really physics heavy and I’m having trouble understanding. One answer even went on to speak about long distance military shooting, the rotation and curvature of the earth, and the fact that the bullet and earth themselves are both gyroscopes. The Magnus effect was mentioned as well. I still dont understand why it’s not possible.
In: Physics
In order for bullet to curve, there has to be a difference in forces that are in symmetrical angles. The reason why a baseball curves or a Magnus effect ball off a dam curves is the sideways (not in the axis of motion) rotation of the ball. A bullet has no sideways rotation. It’s rotating axially to the axis of motion by rifling.
In order to part a sideways rotation, you would have to impart a sideways force on the bullet the minute moments it leaves the very tip of the barrel. A controllable spin. That has real human sized effects. To get that out of sidespin on a bullet that’s traveling 800-1200ft a second, you would need to apply a very large force over a very small time window. Enough that a human can’t generate and enough to probably break the bullet apart as it’s traveling.
In shooting sports there is a phenomenon that causes bullets to tumble midair, we see it in targets and call it keyholing. The bullet strikes the paper target sideways as opposed to head-on. This usually is caused by a defect in bullet or barrel. A defect that has unpredictable effects since tumbling bullets aren’t uniformly rotating in a specific direction.
There is one “shooting” sport where we do curve the bullets for effect. Airsoft is a milsim sport that uses plastic sperical bb’s shot out of a smooth barrel. To elongate the trajectory, a system called hopup is employed where a rubber stop is partially inserted into the barrel. This imparts a backspin on the bb as it travels. The bb trajectory curves up for the first 100ft or so then drops down. Some paintball markers also use this effect for extending the range of the projectile.
Once the bullet had left the gun there os’s no longer any forced acting on it so it will continue on its way in a combined direction of the swing of the gun and the direction the barrel is pointing. It won’t go in a straight curve it will be a straight line.
The other thing to keep in mind of that the amount of sideways movement will be a sum of its time in the air by the speed of arm movement. As you can imagine that won’t be a lot
So it will move just not a lot
If you are thinking of a flick, it won’t be much better. How far could you flick a small pebble out of the barrel of a pistol? Compound that difficulty by the amount of time the bullet spend’s in the barrel which is a defining factor in the amount of sideways force you can impose into the bullet
There has to be some physics in the explanation but I will keep it simple.
To make anything move, you have to push it, or pull it. You have to put some force on it. That bullet is sitting still in the pistol and it will keep sitting there until a force makes it move. Luckily, there’s a bunch of gunpowder behind it to push it down the barrel. But once the bullet leaves the barrel, there is no more force pushing it forward. If you were out in deep space, the bullet would just keep going in a straight line.
Bu the bullet is here on Earth, so a couple of forces are acting on it. Gravity is pulling it down, so it will eventually hit the ground, and air resistance is slowing it down, so it will not be going quite as fast when it hits the ground as it was when it left the barrel.
So, you want the bullet to curve. Okay, fine, but to make it tun, you have to push it or pull it with some force. Otherwise it will keep going in the same direction. No force, no change of direction.
There are two basic forces acting on an object – a rotational force and a linear one.
The rotational force can make the bullet spin or tumble, but it can’t make it ‘curve’ (by itself) because the bullet’s center of mass is within the bullet itself and the only curved path the bullet can take is around its center of mass.
The linear force can’t make it curve either since, rather obviously, it’s linear.
Now, you could potentially curve the bullet aerodynamically by creating a situation where the drag on one part of the bullet was greater than the drag on the other. That’s how you throw a curveball in baseball – the rotation of the ball creates dissimilar drag.
However, this doesn’t work with bullets for two reasons. First, the bullet is rotating the wrong way. It would need to be spinning around an axis perpendicular to the direct of travel, not parallel to it. Second, the bullet is moving far too fast and its drag is far too low. No matter how you spun your bullet, the curve effect would be barely noticeable. You’d need to make special low speed, high drag rounds which wouldn’t be much good at damaging their targets.
Even beyond this, the way they curve bullets in Wanted is completely ludicrous. If you rapidly move the barrel like they’re doing, all you’re doing is creating an additional linear force on the bullet. You’re not ‘curving’ it – at best you’re slightly altering the vector upon which it leaves the gun.
Its spinning the wrong way. If the bullet were spinning laterally to the direction of travel, it could be curved. Because the bullet is spinning parallel to the direction of travel, the wind is travelling across the bullet in at the same speed on all sides, and so there is no difference pulling it in a direction.
The concept of rifling is designed to pull the bullet in a straight line, by causing it to spin parallel with the direction of travel. It’s like, guns are specifically designed that they cant be curved.
If you had a musket, and the barrel was rifled in such a way as to cause the ball to spin “backwards” when holding the gun upright, then it could theoretically be done.
Make sense?
Basically, Wanted is based on a comic where the people had legitimate super powers. Curving a bullet is a thing that you’d need magic powers to do.
Think of firing a bullet like throwing a baseball at someone. When you throw the baseball, there’s no way for you to make that baseball change direction in mid air. It goes in the direction you threw it in. You can add a little spin to it when you throw it, but that baseball is going to go straight. It’s not going to change directions.
Curving a bullet would be taking the bullet that is going straight in one direction, and making it change directions. There’s no way to do that without having super powers.
For the same reason you can’t throw a book across the room and have it curve in a circle around you. In order to make something move or change its motion, you need an unbalanced force to act on it. A bullet is unguided. Once it leaves the barrel of the gun, there are no forces acting on it except gravity and air resistance. Gravity is going to pull the bullet straight down, and air resistance will slow the bullet down and maybe deviate its trajectory depending on the direction of and strength of the wind. There’s no force acting on the bullet that can make it curve around stuff.
Latest Answers