24-01-2006 16:41

Andrew Blair

Re: pic: Our machine is too fast...

Did somebody put a bullet through that windshield?? Maybe you should consider the neighborhood before setting up a robotics shop...

24-01-2006 16:45

Greg Perkins

Re: pic: Our machine is too fast...

this is deffinatly a fake, theres no way a foam ball can shatter a windshield that badly. the root of the impact is way smaller than the size of a poof ball. nice try, funny lol

24-01-2006 16:54

Tom Bottiglieri

Re: pic: Our machine is too fast...

Uh...

Duh?

24-01-2006 19:25

greencactus3

Re: pic: Our machine is too fast...

doesnt say much about that aiming capability haha
next try. brick wall.

24-01-2006 21:29

Arkorobotics

Re: pic: Our machine is too fast...

I know a poof ball can't do that.. but who says that is not a metal ball painted like a poof ball?

Plus our new robotics shop is the schools old auto shop that closed down last year because people were breaking the cars that we worked on... this is one of the victims that sayed. But now our huge auto shop is our new huge robotics shop.

24-01-2006 22:21

elknise

Re: pic: Our machine is too fast...

lol, that is hilarious.

I can't believe people actually post saying why this might not be possible.

But it is funny.

24-01-2006 23:02

dlavery

Re: pic: Our machine is too fast...

Ahem. Care to make a little wager on that?

Before anyone volunteers too quickly, I would remind you about the group of professional engineers that adamantly proclaimed that there was absolutely no way that a piece of lightweight foam could ever punch a gaping hole in a carbon-carbon reinforced panel on the leading edge of a wing.

I am not bringing this up to be maudlin. Rather, it is done to illustrate the point that we need to be very, very careful when making blanket statements. As engineers, we should understand that physical phenomena are typically bounded by certain parameters of performance. When we make assertions regarding those phenomena, it must be done in the context of the parameters relevant at the time. We must take care care when discussing these phenomena not to make statements such as "event X is always true" when what we really mean is "event X is always true when condition Y is true, otherwise it isn't." Otherwise, imprecision and inaccuracy will inexorably find their way into our communications. When that happens, we run the risk of losing the trust of the public and being perceived as an error-prone, lackadaisical profession.

-dave

24-01-2006 23:03

Wetzel

Remember the 3rd law...

I'm sure the foam ball could shatter the windshield.
Can a box of tissues decapitate someone?

Dave, you beat me too it.

Wetzel

24-01-2006 23:15

KenWittlief

Re: pic: Our machine is too fast...

unfortunately that windshield is characteristic of what happens if you dont wear your seat belt.

That may not be what happened to this car, but when it happens thats about where your face hits :c(

24-01-2006 23:23

Arkorobotics

Re: pic: Our machine is too fast...

Oh come on! You've got to be kidding! There is no way in this world that a foam ball did that damage. When the people came to rip up the car and sell it (for scrap, by the way this car is on it's way to death row, we need to rip it up and sell the parts) we had to take a sledgehammer to it (breaking the windshield) and it did little damage of a small little hole and a huge crater. Plus there are other cracks in other places.


P.S. - no "KenWittlief" nobody was in the car and no one was hurt during the "destruction", but ya I bet you can seriously get killed if you don't have your seat belt on and you will create a larger hole than that and probably fly throught the windshield.

24-01-2006 23:43

Wetzel

Re: pic: Our machine is too fast...

We actually spent a good deal of time talking about the physics of an accident in my trauma class this week and last. F=ma. You can apply as much force as you want if you can control either the mass or acceleration. When you negatively accelerate the ball by hitting the windshield, you transfer that energy to the windshield. The ball may not have all that mass, but you fire it fast enough and it will shatter that windshield.

Wetzel

24-01-2006 23:57

Arkorobotics

Re: pic: Our machine is too fast...

Well your acceleration better be reallllyyyyy high up! but doesn't material count? and compression?

25-01-2006 00:11

KarenH

Re: Remember the 3rd law...

Don't know about a box, but a large cardboard color wheel just about knocked out my Home Ec teacher.

I wanted to laugh when I first heard about this. How could that color wheel (on lightweight cardboard, maybe 18 inches dia., max.) hurt anyone?

Well, before lunch some girls were throwing it like a Frisbee, and it hit our teacher in the head edgewise. When I showed up for class after lunch, we were told she was still lying down in the nurse's office, feeling faint.

I bet it could have decapitated her, if it had enough velocity and hit her in the neck.

25-01-2006 00:15

Wetzel

Re: pic: Our machine is too fast...

F=ma. The force will equal the mass of the ball times the acceleration.
Acceleration is the rate at which an object changes its velocity, so the compression will lower the acceleration by some amount. By slowing the ball over an extra 2 inches, you have a smaller acceleration. With a smaller acceleration you have a lower force.

All that means is you need a higher starting velocity.

Wetzel
PS: If someone who has taken actual physics rather than physics of a body in an accident and can explain it better please do.

25-01-2006 01:40

Alekat

Re: pic: Our machine is too fast...

Sounds to me like you did a great job. As long as you can establish that your poof ball won't have to exceed the speed of light to punch a hole, it is possible.

two things you have to remember from physics:
1. F=ma
2. You can't push on a rope.

25-01-2006 08:16

KenWittlief

Re: pic: Our machine is too fast...

what if the foam ball was soaked with water when it hit, and it weighed as much as, oh.. lets say a pumpkin?

25-01-2006 08:58

greencactus3

Re: pic: Our machine is too fast...

ooh has anyone tried that? its cold around here for watergames but.

25-01-2006 09:55

artdutra04

Re: pic: Our machine is too fast...

If we tried that, the ball would probably freeze solid even before it got to the car.

25-01-2006 10:07

kawelch

Re: pic: Our machine is too fast...

This is beginning to sound like a job for MythBusters and I don't care what anyone says I would bet a month's salary that they'd be able to get a Poof-ball to shatter a car window.

25-01-2006 10:40

EOC

Re: pic: Our machine is too fast...

If the foam ball was dunked in liquid nitrogen, it could work.

25-01-2006 10:52

KenWittlief

Re: pic: Our machine is too fast...

If the poof ball were launched in a vacuum then it could go fast enough to break a windshield

it might have to be going 18,000mph, but in space...

[this is rapidly turning into a 'how many engineers does it take....' contest :^) ]

25-01-2006 23:54

Arkorobotics

Re: pic: Our machine is too fast...

Wouldn't the ball disintegrate in mid air or when it hits the windshield