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Can you kill someone if you throw a pritt stick of the eiffel tower

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Jesus! The simple answer is no, unless it hits a person with a very weak skull in a very special way!

F=ma is not the right formula, it simply tells you the force acting on the pritt stick caused by gravity, or the force required to produce an acceleration. In the case of terminal velocity, a pritt stick is very light hence using F=ma, you can get the force required by air resistance to stop the pritt stick accelerating, mass is measured in kg so its not gonna take much force. hence its not gonna be moving that quick. You can work out the momentum, P=mv m and v are going to be pretty small so isn't going to have that much momentum.

Reply 61

Mr. Gutsy

Maybe if it triggered a misplaced landmine that just so happened to be within the vicinity of the 'someone' in question, but otherwise I doubt it would kill them. It could even hit a wild dog and bewilder them, whereby they go berserk and start attacking people, killing numerous small children. The possibilities are endless.

Reply 62

Ramses II

I think that even at terminal velocity it wouldn't manage more than very stingy.

Reply 63

Mm_Minty

They tested the coin off of the empire state building on mythbusters and that seemed ok so I'm guessing a prit stick wouldn't cause too much damage either?
Might depend on whether it was capped or noth though :p:

Reply 64

danny111

Original post by Septimoose

Force = mass x acceleration.
mass= 0.2kg acc.=9.8m/s^2
Force = 1.96N (I don't think this could kill a person)

My logic is probably flawed, but that bonfire parteh was DAAAAAAAAMN GOOOOOOOD

I quit physics a while ago but where in that calculation do you take into account distance travelled?

Reply 65

Cicerao

I'd be aiming for the tat sellers myself.

Reply 66

sand4

Original post by Asclepios

How do you know all this stuff. I pray to god its not A level physics

Most of it is A-level physics. To work out terminal velocity there is an equation on the wikipedia page for terminal velocity which I used.

Whether or not the pressure would crack the skull is a guess and could be very wrong.

Reply 67

FF-

Original post by Ellastar

Nah. You can kill 5 if you throw a pig off it, though.

super pig will survive thou :biggrin:

Reply 68

username310124

That would be a sticky situation. :awesome:

Reply 69

CJN

Original post by CB91

That would be a sticky situation. :awesome:

Already done, already done :tongue:

(And no it wasnt me who negged you)

Reply 70

username310124

Original post by CJN

Already done, already done :tongue:

(And no it wasnt me who negged you)

Too slow.

And, meh, I dont really care about rep. :dontknow:

Reply 71

Bobifier

Original post by Charzhino

Its a rough estimation

For a rough estimation, you'd need a rough estimation for a. Unfortunatley, you don't really have anything like that either. I guess you could pick a random number, but that's about as rough as it comes.

Reply 72

usainlightning

Original post by History-Student

Dunno about a pritt tick, but a coin off the very top could cause some damage if it hits someone.

Hasn't anyone on here heard of terminal velocity?

Reply 73

Left Hand Drive

IM taking my gf to paris for her birthday! I'll report back in feb. Thats if I can avoid the 'feds'!

Reply 74

Noble.

Original post by usainlightning

Hasn't anyone on here heard of terminal velocity?

You're right. Given the drag coefficient of a cylinder, it makes no difference whether it was dropped from the top of the Eiffel tower, or at 30,000 feet. However, I'd still rather not have an object travelling at ~60mph fall on my head even if it is only 0.06kg.

Reply 75

KingMessi

Original post by CJN

If it could have an infinite velocity then it would almost certainly be able to kill someone. But when falling in air objects have a terminal velocity that they reach, whereby it can't fall any faster.

And due to this, the decelleration caused by the head of a person, will be smaller - as acceleration is change in speed divided by time (and obviously a smaller speed going to 0 is a smaller change).

But there are loads of approximations and uncontrolled variables.

Oh, okay. That makes sense to me. Thank you.

Reply 76

Entangled

It probably wouldn't kill you. You'd be in a pretty sticky situation though.

Reply 77

xoxAngel_Kxox

To be honest with you, I think you could probably kill someone with a pritt stick standing right next to them if you hit them with it hard enough.

Reply 78

Oxmatt

Original post by Slk3

"It hasn't got enough mass" - I'm pretty sure a pritt stick has about the same mass as a bullet.

I'd say that a large pritstick weighs about 40 grams, while a bullet would have to be at least a little more than that. http://cgi.ebay.co.uk/LARGE-PRITT-STICK-40g---P%26P-offers-available_W0QQitemZ230421704629QQcmdZViewItem?rvr_id=163938696621&rvr_id=163938696621&cguid=21013cbe12c0a0aa15814f71fffd4222

Original post by Slk3

"It will reach terminal velocity" - So will an anvil falling on someone from the top of the Empire State Building.

I know this, but the fact that the anvil has a much higher mass means that its momentum will be much larger. My point was that after a certain point it doesn't matter how high you drop an object from, as its momentum will remain constant.

Original post by Slk3

Points 4-6 are debatable, and 7 is not even a proper reason, just a statement of opinion.

What we should be talking about here is the amount of kinetic energy the pritt stick has just before it impacts. This depends on whether it reaches terminal velocity in time and how much it weighs. I'm sure someone keen enough could calculate this knowing the mass of a pritt stick and the height of the eiffel tower. Pressure drag mentioned in some posts is also relevant, but is relevant only to how much its terminal velocity is (and therefore the amoutn of energy it has just before impact). Then a doctor/medic would need to tell you what would happen if something with that shape impacted with that force.

Firstly, it wasn't meant to be a rigorous proof. Simply me offering reasons why you wouldn't expect a pritstick to be able to kill someone.

All I was saying is that the impulse of the pritstick is small enough that common sense tells you it won't kill someone. Terminal velocity is 90 m/s for a skydiver in a pencil drop position, so it would be sensible to say that this is the speed of the pritstick. The mass is 4 x 10^(-3)kg so the impulse will be 0.36Ns. If this happened in one hundreth of a second, then the force will be 36 Newtons (assuming that the prittstick stops, i.e. all the kinetic energy is transfered in to heat/damage in the head). And a boxer can exert up to 5000 Newtons http://www.livescience.com/health/humans-can-take-a-punch-100203.html So I doubt that a pritt stick could kill someone.

Sorry, bored this morning :biggrin:

Reply 79

Asclepios

Original post by Entangled

It probably wouldn't kill you. You'd be in a pretty sticky situation though.