» Thu Aug 19, 2010 1:16 am I have not been shot with an arrow, so I will trust you when you say that they carry a significant amount of force. And I hope, in turn, that you will trust me when I say I understand physics. Yes, the arrow does expend all its energy in the target because it travels relatively slowly, meaning that it has less momentum than, say, a bullet. (By the way, bullets are not designed to go through people. Any bullet that goes through its target is wasting energy, and most bullets are in fact designed to expend as much energy as possible in the target.)
OK, momentum is m * v. Let's say that we have an arrow weighing 400 grains (not an unreasonable amount). This is 25.9 grams, or .0259 kg. Let's say that the speed of said arrow is 100 m/s. These figures are more in line with modern bows--English longbows, for example, would shoot arrows at about half that speed, but the arrows would also probably weigh more. Anyway, these figures give us a momentum of 2.59 kg*m/s. Now let's look at a .45 caliber round. Just going by the info for various rounds on Wikipedia, we have 10.7 g at 320 m/s on the low end (momentum = 3.42 kg*m/s) and 12.0 g at 330 m/s on the high end (momentum = 4.476 kg*m/s). If a .45 caliber round shot into a person and not going through does not knock them back, it is physically impossible for an arrow to knock them back.
As for an arrow stopping a grown man running in his tracks, well, sure--people will generally stop running when they get hit with an arrow. A bullet will generally accomplish the same thing. But neither projectile has enough momentum to physically stop a running person. They will not stop as if they had just run into a brick wall. The reason that people stop when they are hit by a projectile is because they have been wounded too greatly to continue running. None of this affects momentum.
Maybe I'm misunderstanding the term "knock-back." I take it to mean "physically knocking some one back." Like what might happen if you hit someone with a baseball bat, which has a lot more momentum. If we're simply talking about stunning or staggering someone, then yeah, sure, an arrow can definitely stun or stagger a person. But it will not significantly affect that person's momentum--in other words, if they are standing still, they will not go flying, and if they are moving, they will not stop dead in their tracks.
Sorry if that was a little picky. Also, apologies in advance if further replies are delayed, as my visits to the forums aren't always regular.
OK, momentum is m * v. Let's say that we have an arrow weighing 400 grains (not an unreasonable amount). This is 25.9 grams, or .0259 kg. Let's say that the speed of said arrow is 100 m/s. These figures are more in line with modern bows--English longbows, for example, would shoot arrows at about half that speed, but the arrows would also probably weigh more. Anyway, these figures give us a momentum of 2.59 kg*m/s. Now let's look at a .45 caliber round. Just going by the info for various rounds on Wikipedia, we have 10.7 g at 320 m/s on the low end (momentum = 3.42 kg*m/s) and 12.0 g at 330 m/s on the high end (momentum = 4.476 kg*m/s). If a .45 caliber round shot into a person and not going through does not knock them back, it is physically impossible for an arrow to knock them back.
As for an arrow stopping a grown man running in his tracks, well, sure--people will generally stop running when they get hit with an arrow. A bullet will generally accomplish the same thing. But neither projectile has enough momentum to physically stop a running person. They will not stop as if they had just run into a brick wall. The reason that people stop when they are hit by a projectile is because they have been wounded too greatly to continue running. None of this affects momentum.
Maybe I'm misunderstanding the term "knock-back." I take it to mean "physically knocking some one back." Like what might happen if you hit someone with a baseball bat, which has a lot more momentum. If we're simply talking about stunning or staggering someone, then yeah, sure, an arrow can definitely stun or stagger a person. But it will not significantly affect that person's momentum--in other words, if they are standing still, they will not go flying, and if they are moving, they will not stop dead in their tracks.
Sorry if that was a little picky. Also, apologies in advance if further replies are delayed, as my visits to the forums aren't always regular.
Ok Redo the phisycs with the following pratical and historical data:
Consider my bow, 70Pounds of drawn and around 0,330 KG (not grains) arrow weight. This is a bow at heavy end spectrum, few things are not allowed to be hunted with it. Consider with hunting tip, this a classic hunting bow for medieval references.
Speed is around 1.25 sec for 60 meters which gives around 172 km/h on the average speed. (i never had the chance to fire the hundred meters) Consider also that at 60 meters i am able to trespass 5cm (2 inches) of wood (Yes, i missed the target and it ended up trespassing the support which collapsed), the arrow whas half body the other side which mean a little mor than 30cm (A feet)
Historical data show that the average war longbow would be around the 100 pound and the arrow would have a weight averaged around the 0.4 kg probably going even more than 0.5 kg for heavy target (knights) althought the tip wasn t the regular "triangular shape" but was needle like ending on a flat blade usually no larger than the shaft.
Don t know the average speed for a longbow, never had the pleasure to fire one, much less a warkind one.
And what he was talking about is stopping power. And the 45 caliber was designed especially to stop men in their tracks and it usually does it, althought a super 380 is known to have a superior stopping power.
in you calculation your not counting hydrostatic shock, skeleton kinetic integration and the like.(A small fast bullet will pass trought the bone, a large slow bullet will crush by impact and the skeleton will be affected by the shock, much like the way a punch in the torax can stop you on your track enven if a "2 knuckles punch" like Aikido).
About bullets, bullets are designed today to dismantle and/or bounce inside the victim, that why usually when your hit by some 3.39, 5.56 and 4.56 (or something around it) on the trunk and a bone is hit, you may may very well ,if still alive, end up opened like a fish because they will have to hunt for the bullet fragments and possible hemoragies the fragments caused while using your body as a bouncing field.
Now to the OP, i prefer the 2 obviously, its the less imperfect.
Now people Personal strenght does not make you shoot arrows faster.
Strenght only determine if you will be able to pull the string or not, the BOW does all the strenght.
If your not able to pull the bow, you won t be able to aim, so forget it.
What would be interesting in game is the ability throught diferenciated material to create diferent bow strenght. So a weaker character would be able to draw a yew bow but not a glass or daedric bow. (althoguht what make the bow strenght is the thickness of the bow. But a too thin bow will break while your pulling the string with usually some nasty effect like the broken part your not holding shooting toward you.
