9/11 Physics from Non-Experts

[beachnut]

It seems to me he's finally made a testable prediction.

Anyone got a high speed camera, a brick and some eggs they don't like?

Me got brick and bunch of eggs.

The golf ball will be a solid stone type egg

 

[rwguinn]

It seems to me he's finally made a testable prediction.

Anyone got a high speed camera, a brick and some eggs they don't like?

If he is using velocity as most of his ilk do, i.e. speed, he wolld be correct. it doesn't gain SPEED. IT actually reduces speed, which means that there is an acceleration from somewhere
What it actually does is gain an acceleration vector opposite that of gravity, so there is a net reduction in acceleration, which means that there is a velocity vector generated opposing the instantaneous falling velocity vector, which means that it gains negative velocity--but it doesn't go to zero, which means there is a force acting upward on the brick, and since any force acting upwards counteracts gravity, the egg won't break.
Is that what he is saying?

 

[beachnut]

If he is using velocity as most of his ilk do, i.e. speed, he wolld be correct. it doesn't gain SPEED. IT actually reduces speed, which means that there is an acceleration from somewhere
What it actually does is gain an acceleration vector opposite that of gravity, so there is a net reduction in acceleration, which means that there is a velocity vector generated opposing the instantaneous falling velocity vector, which means that it gains negative velocity--but it doesn't go to zero, which means there is a force acting upward on the brick, and since any force acting upwards counteracts gravity, the egg won't break.
Is that what he is saying?

The brick will speed up and only a slight change in velocity due to running the momentum would be present.

But the brick is going to speed up as it crushes the egg.

In fact on many soils a solid egg, ie golfball will be driven into the ground as the brick accelerates, and pushes the egg into the ground, or is the ground pushing up?

Our expert has already said that negative acceleration is allowed, and could happen. I am not sure what eggs he has, and I guess there is a brick you could use that would slow down as it cracks and egg but not my brick.

 

[rwguinn]

The brick will speed up and only a slight change in velocity due to running the momentum would be present.

But the brick is going to speed up as it crushes the egg.

In fact on many soils a solid egg, ie golfball will be driven into the ground as the brick accelerates, and pushes the egg into the ground, or is the ground pushing up?

Our expert has already said that negative acceleration is allowed, and could happen. I am not sure what eggs he has, and I guess there is a brick you could use that would slow down as it cracks and egg but not my brick.

AHHH! The MWO Brick of DOOM!
We'll all be killed!

 

[jaydeehess]

Ridiculous, the brick will continue to acellerate right through the eg. Its acelleration will be less than 9.8 m/s, that's all. Its acelleration will not reduce to zero.

To my mind the velocity will continue to increase even if the egg slows the acelleration slightly. that reduction of acelleration will be short lived as well as once the integrity of the egg is broken it will offer only miniscule normal force.

This is what happened at the WTC towers. there was an upward force due to the resistance of the building and the downward force of impact and due to the effect of gravity on the mass. the lower portion of the building was neither capable of withstanding that total force in any fashion but even more, that downward force was not being directed immediatly at the strength members of the building, its columns. The floors could hold only a small fraction of the mass of the building thenselves let alone that of 10 or more stories.

 

[rwguinn]

Ridiculous, the brick will continue to acellerate right through the eg. Its acelleration will be less than 9.8 m/s, that's all. Its acelleration will not reduce to zero.

To my mind the velocity will continue to increase even if the egg slows the acelleration slightly. that reduction of acelleration will be short lived as well as once the integrity of the egg is broken it will offer only miniscule normal force.

This is what happened at the WTC towers. there was an upward force due to the resistance of the building and the downward force of impact and due to the effect of gravity on the mass. the lower portion of the building was neither capable of withstanding that total force in any fashion but even more, that downward force was not being directed immediatly at the strength members of the building, its columns. The floors could hold only a small fraction of the mass of the building thenselves let alone that of 10 or more stories.

You win the cigar (you may chose a bubble-gum cigar, if you wish).
The acceleration will, indeed decrease, by a tiny amount. It does not go to zero, however. This means that the brick is still accelerating! Which also means that the velocity will continue to increase!
Is science not wonderful?

 

[Horatius]

I really need to go back to school, and remember how to diagram all this.

Clearly, at the moment of impact, there is some decrease in the acceleration. I wonder if we can model it as a spring?

Prior to impact, we have F_brick, the force of gravity on the brick, F_egg, the force of gravity on the egg. -F_egg is the reaction force from the ground against the egg.

At impact, F_brick, F_egg and -F_egg would still exist, but we would have a new set of forces, the "spring" action of the egg deforming. Call it F_def. This is caused by the brick on the egg, so we'd also have -F_def, from the egg acting on the brick.

So, initially, the net force on the brick would be F_brick - F_def. So the acceleration would be lower, but unless the magnitude of F_def was equal to or greater than F_brick, it will continue to accelerate.

As the egg deforms, F_def increases. It starts at zero (the moment of contact), then increases to some maximum. The maximum would be dictated by the breaking point of the egg.

Since the brick has an initial velocity, to survive, the egg must not only be able to resist the weight of the brick, but also apply some additional force to decelerate the brick to zero, before the egg fails. So to stop the brick, the egg's failure point (F_defMax) would have to be some value greater than F_brick.

Since we know eggs get crushed by bricks (we do know that, right?), clearly F_defMax is less than the above scenario. We need to determine what F_defMax is. If an egg can support the weight of a brick that is gently laid on it, it could be exactly equal to F_brick, or a bit more.

As shown above, if F_def is less than F_brick, it will continue to accelerate, albeit as a lessened rate of acceleration. At some point, as the F_def approaches and passes F_brick, the acceleration would drop to zero. As F_def increases even more, and approaches F_defMax, the brick actually would slow down a bit.

However, at the point of egg failure, F_def instantaneously drops to zero, and the brick continues on unimpeded.

So the question becomes, how much greater than F_brick is F_defMax, and how much does the brick slow down as a result of that difference, and (when considered as a complete event, from contact with the egg to contact with the ground), does the brick undergo net positive or net negative acceleration?

I'm betting net positive, but this guy might have some pretty strong eggs.



Unless I missed something.

 

[Overman]

E = m*c^NWO

 

[SYLVESTER1592]

You did realize that he won't accept this as a debunking, did you. He will claim hairsplitting, misrepresentation of his idea and return to the Fnet=0 mantra.
Still...worth the effort

 

[beachnut]

I need about 5 to 10 times faster frames.

60th of a second the brick was gaining velocity. But in the last frame the brick is on the sand, golf ball buried, then the brick continues at 1/3 speed or so into the sand for the next 1/60 sec., it even bounces and comes to rest in about the same postion here in 7/60 of a second.

The golf ball was buried, the 1/60 of a second is not enough resolution to see if the golf ball and brick were accelerating sometime during the last 1/60 second frame into the sand. Faster frame rate is needed, 600 per second could do it.

What about an egg, not a model of a egg.

 

[babazaroni]

oops, already stated.

 

[beachnut]

I've got a feeling that the brick will not change velocity if the F_def is equal to Mass_brick X 9.8M/S.

Mackey will set us straight.

I finished my egg vs brick, the brick accelerated as it crushed the egg. The young physics dolt must eat the sandy egg words he stated as -

Answer from Yandros42 Physics expert --

No idiot. The brick won't accelerate once it has reached the egg, because the net force is zero. The kinetic energy built up by the falling brick will most certainly shatter it. But if you were to take high speed recording of the brick smashing the egg you would find that the brick was not gaining velocity as it smashed the egg.

Oh, but it did gain velocity. Where did he get his physics degree. We need to know if he was on earth. Maybe his eggs are bigger and gravity is no as great.

What did he really mean. And do I have to post the brick crushing the egg or will you believe me the brick accerates thru the egg?

With these frames from the famous 60 frame per second back yard what the hell is a retired airforce pilot with a masters degree in Electrical Engineering doing with an egg and a brick film.

I always wanted to do the bowling ball through panes of glass and prove someone else wrong who said it would take like 40 seconds for a bowling ball from 1300 feet to go through 110 panes of glass spaced as floors of the WTC. I get to pick the glass.

Actually there is enough information here to measure that the brick's acceleration is not altered much by the egg. Where did this kid go to school? (yes I need a flat field lens and more frames per second)

BTW, I can see him now after interview, he will be rationalizing why he was not hired.

 

[Horatius]

The golf ball was buried, the 1/60 of a second is not enough resolution to see if the golf ball and brick were accelerating sometime during the last 1/60 second frame into the sand. Faster frame rate is needed, 600 per second could do it.

What about an egg, not a model of a egg.

Where are the Mythbusters when we need them?

 

[Horatius]

What did he really mean. And do I have to post the brick crushing the egg or will you believe me the brick accerates thru the egg?

Did you try just gently putting the brick on the egg? If it can't support the weight of the brick under this condition, the whole question is moot, as the F_defMax would be less than F_brick, and the net force/acceleration would never go below zero.

 

[Furcifer]

"No idiot. The brick won't accelerate once it has reached the egg, because the net force is zero." -YandrosIQ42


There's no way someone could get an "A" in physics and make this statement. I'd like to see this "net force" equation on paper, I can't imagine how you would even start to show this?

 

[beachnut]

Did you try just gently putting the brick on the egg? If it can't support the weight of the brick under this condition, the whole question is moot, as the F_defMax would be less than F_brick, and the net force/acceleration would never go below zero.

You mean the easy way. Let brick accelerate from F=ma=0 and see if gravity and the ground pushing up break young egg?

Do you want me to do another egg during lunch or afternoon nap time?

 

[Horatius]

Do you want me to do another egg during lunch or afternoon nap time?

Whenever you can fit it into your schedule, as long as it's on my desk by 5pm.







Of course, we have to get you to do it. If I do it, he'll claim I used a heavier brick, or some such thing.....

 

[beachnut]

Whenever you can fit it into your schedule, as long as it's on my desk by 5pm.







Of course, we have to get you to do it. If I do it, he'll claim I used a heavier brick, or some such thing.....

The brick was at rest over the egg, the egg was accelerated into the ground by gravity assisted by brick. I have no idea how the brick crushed the egg since it can not according to whats-his-name accelerate. I have no idea what to call the ability of brick to end up on the earth after it was on top of egg. The egg is slowly cooking in the afternoon sun.

What do you call it when something moves?

It looks like the brick on top accelerated and then stopped on lower brick and I think the egg was zeroed out by some unknown zero force.

5 to 7 frames, 60/sec, into the brick acceleration, the egg looks elastic. How do you ban people from YouTube comments, and erase them? I think those who erase and ban need to be labeled as such; there needs to be a place where we can see the things banned by the censorNAZIs out there.

 

[Horatius]

What do you call it when something moves?

I think the term is "debunkeration".

So we see that F_defMax is less than F_brick. So the net force on the brick will always be directed downwards, and there will always be some net downwards acceleration, even if it is some small amount less than freefall.

Any bets on what he says now? I bet he complains that the egg was on its side, rather than it's end, since it's stronger in that direction.

 

[qarnos]

I finished my egg vs brick, the brick accelerated as it crushed the egg. The young physics dolt must eat the sandy egg words he stated as -

Hmmm... your brick had a very obvious tilt as it hit the egg. It should have bounced off and slid to the side, no?

Seriously, a much easier experiment would be to make a cylinder out of paper, place it end-on on the ground and gently place a heavy brick on it. By Net Force Boy's reasoning, the paper cylinder should be able to resist the brick.