Physics problem

Canyarion · 03-07-2004, 11:14 AM

Ok I´m kinda in a debate with somebody on a different forum. We were talking about how Legolas fired 3 arrows at once into the Mûmakil (the big elephant).

I stated that by firing 3 arrows at once, every arrow would only have about 1/3 of the power that an arrow could have had if Legolas had fired only 1 at a time.

He asked his dad

that is supposed to be a math teacher and 'knows physics' and he says I'm wrong.

Anyway, this has to do with N=m*a. There's 3 times as much weight (m), Legolas' strenght remains the same (N) so a is 1/3 of what it would have been with 1 arrow...

Less a means less speed, less speed means less damage...
But since you have 3 arrows, it makes up with the damage, so the total damage with 3 = the same as with 1.

So I'm right, he and his dad are wrong.

See the picture and tell me if I'm wrong or right please.

BTW the dude said that each arrow would have the power of a single-shot arrow.

Blackmane · 03-07-2004, 12:13 PM

Lemme go find out. Your view makes some sence but it may be oversimplifying this problem.

ZebraRampage · 03-07-2004, 12:14 PM

In my mind, what you said is just common sense. How could shooting three arrows at a time be more powerful than one. You're using the same about of power, but you have to put it into three arrows, giving them 1/3 of the power you give them, as opposed to giving all the power to the one arrow is you just shoot one. It's just common sense..

Happydude · 03-07-2004, 12:48 PM

you're wrong, because you don't put the power into te arrows...you put it into the string of the bow, which gives the arrows the push.

and since the power remains the same, the push remains the same for the arrows. so the power of the 3 arrows would be triple that of just 1. because each arrow gets the same push.

thatmariolover · 03-07-2004, 02:08 PM

When the string is pulled back, it has a lot of potential energy. When you let go of the string, only a tiny amount is transferred to the arrow. Three arrows or one, they're just tiny pieces of wood. The energy in the bow is so great that it will not be used up by pushing them, so they're all going to have the same force behind them.

Understand? If not, I'll try to help you understand better.

Neo · 03-07-2004, 02:11 PM

mariolover is correct

Happydude · 03-07-2004, 02:36 PM

isnt that more or less what i said?

thatmariolover · 03-07-2004, 03:00 PM

Quote:

Originally Posted by happydude666

isnt that more or less what i said?

It is, I just thought I'd try to clarify it a bit. You were right. You knew what you were talking about as well as anybody else. I just thought I'd try to phrase it another way, and add a bit.

Happy Dance · 03-07-2004, 07:11 PM

wait.... but the 3 arrows will have more mass then only 1. so im pretty shure that the force of Impact Will be Less then one arrow. There for: the power wont be devided eaqually into 3 from the start ...

only if u have 1 heavy arrow = to 3 normal once then the force of impact will be the same !

Neo · 03-07-2004, 11:56 PM

Except it's not a closed system of arrows.

Hero2 · 03-08-2004, 12:25 AM

If a train hits a squirrel the squirrels gone if it hits three squirrels they still die.

thus the bow string has soooo much force it doent matter if it is pushing three arrows or one they still go. IMO

What I want to know is ifs its acually possiable to shoot three arrows at one from a regular bow no guides ect..

Happy Dance · 03-08-2004, 12:33 AM

Quote:

Originally Posted by Hero2

If a train hits a squirrel the squirrels gone if it hits three squirrels they still die.

thus the bow string has soooo much force it doent matter if it is pushing three arrows or one they still go. IMO

What I want to know is ifs its acually possiable to shoot three arrows at one from a regular bow no guides ect..

yes... but the first
squirrel will sotp some of the force of the train

so mass matters =P

thatmariolover · 03-08-2004, 12:49 AM

No. Period.

If I put one orange in a catapult, it will go 100 meters. If I put 3 oranges in the same catapult, they're still going to go 100 meters. That doesn't change.

Even air resistance wouldn't change because they're still essentially three separate things.

Great squirrel referance by the way.

Crono · 03-08-2004, 03:33 PM

Quote:

Originally Posted by Happy Dance

yes... but the first
squirrel will sotp some of the force of the train

so mass matters =P

But the squirrel's mass is irrelevant (sp) to the train's mass. It's like your mass compared to the Earth, according to physics laws, you are also "pulling" the Earth (equal reaction for every action), so if you went 5 000 km into space you would still be pulling the Earth, but your mass compared to the Earth's makes it irrelevant.

If a train with a mass of 40,000 kg hits a squirrel that ways like.. .5kg ... then you won't notice the difference. If the object it hit was much bigger, then you'd see the difference.

If each arrow weighs say... 0.1 kg (probably less than that, or maybe not, but whatever), and the bow weighs 2kg, then the mass of 3 arrows becomes insignificant to the force put out by that bow (F=ma).

surfin4lifer · 03-24-2004, 03:37 PM

In actuallity the arrows probably wouldn't do any damage at all to an Elephant that large, most in part because its going to have some hella this skin, and personally I don't think and arrow is gonna puncter anything like that. It'd be like sticking an arrow through a flak jacket.