January 28th, 2008

#859: It's not an estimate. Physics is my friend.

In the comments for #858 Anonymous poster told me, "For what its worth..I think your speed calculations are grossly underestimated." I was writing a reply, explaining why I could not be wrong--it is literally physically impossible--and realized it was far too long for a comment. But my calculations are calculations, not estimates: I used actual physics to come up with my numbers.

That's why I said "calculations" and not "estimation". Its true that my description is leavened with "about" and "approximately" but that's because I didn't want to write the precise numbers, which were 2.09165 seconds, leading to a velocity of 95.61828 feet per second, which is 65.19428 miles per hour.... That gets tedious, and the rounded numbers were close enough for my purposes. (And I have, in fact, truncated the numbers. Actual speed at impact: 65.194287781876016725571846165079 miles per hour....)

But I did "run the numbers"--twice, to make sure I'd gotten the correct answer...and I'm sorry to say that unless the information I got from the article was wrong, the answer I got cannot be wrong. It's the laws of motion in action!

So let's take a look at things again:

Distance equals 1/2 acceleration times time squared: D=0.5*a*t^2.

The car could not possibly fall faster than it did. In order to strike the tree 15 feet from the ground it had to fall for two seconds. In a one G field, it takes a full second just to fall 16 feet, but at the end of two seconds, you've fallen 64 feet. (And at the end of 2.09165 seconds, you've fallen 70 feet.) That's why we say an acceleration is some measure of distance per second per second: you add X many units per second of velocity every second that you're under acceleration.

The article says that the car left a runway that was 85 feet above the surrounding terrain, traveled 200 feet, then struck a tree 15 feet from the ground. It therefore had to fall 70 feet before striking the tree. In order for the car to have enough time to fall 70 feet--traveling a distance of 200 feet after leaving the runway but before striking the tree--it could not have been moving faster than 70 miles per hour.

As I said in my initial post, at 100 MPH they would have fallen only 29 feet before striking the tree, and they would have hit it 56 feet above the ground rather than 15. At 100 MPH they would have had only 1.3 seconds of "air time", and that's not enough time to fall 70 feet. It's only enough time to fall 29 feet. As I said.

According to the information given in the article, it can't be otherwise.

* * *

However, there is one point I insufficiently amplified, which I will amplify now.

After you fall for two seconds, your speed is 64 feet per second, which is about 43 miles per hour. The car did not just slam into the tree with a horizontal speed of 70, but with a vertical speed of 43 MPH.

If the car had not hit the tree, those five kids would be just as dead as they are now, but for a different reason.

The typical car is not built to have much crash protection along its yaw axis. The vertical drop test is not one that is usually evaluated by manufacturers or government safety inspectors, because cars are not meant for stunt driving. Most people do not operate their cars in a regime where such a collision is likely.

Although the chassis of a car has significant rigidity to withstand road-induced flexion and compression, it's desgined to operate in a rather limited envelope and does not have the strength to withstand a generalized impact at such speeds.

If I am generous, and allow 0.1 second for the duration of acceleration, then the car experienced 20 gravities of acceleration when it struck the ground. That alone would have totaled it even if it had not struck the tree. 0.1 second is a long time for a collision; I'm deliberately overestimating the compressibility of dirt in order to make a point: a car pancaking onto the ground at 43 MPH is going to be destroyed. In fact, a duration of 0.05 seconds is probably more reasonable, shooting the acceleration to 40 G.

And since the human spinal column does not respond well to compression, I wager those kids would also still be dead.

It is possible for a human to survive much greater shock than 20 G--see this Wikipedia article on John Stapp--but he has to be strapped in securely. A typical automotive safety harness--while safe in most collisions--is not sufficient.

The other factor is, of course, that the car would have pivoted on its pitch axis.

Anonymous poster claims to have survived a 70 MPH collision with a tree, and I don't disbelieve him--but his collision and this one occurred under differing circumstances.

The BMW was not, as we have established, merely striking a tree; it was striking a tree after falling 70 feet. But it was also rotating about its center of gravity.

The front wheels left the runway first. This means the front end of the car began falling before the rear--a few milliseconds--which means that the car, as it fell towards its rendesvous with destiny, had a slight moment of rotation about its center of gravity induced by this asymmetrical application of gravity.



This diagram shows all the forces acting on the car. There is its residual speed, Vs, its velocity due to the acceleration of gravity Va, and its rotational component, omega, which I'll represent in text here with "w". W is the key to why the car experienced such enormous damage and disintegrated so spectacularly.

Cars are designed for collisions in the "x" plane--the plane defined by the car's roll and pitch axes, the plane which is perpendicular to its yaw axis. Most collisions occur in this plane. The car is designed for a certain amount of "rollover protection"--it can withstand a certain amount of impact on its roof--but nothing like what it can stand from the front or sides.

I would wager that Anonymous' accident involved skidding off road and striking a tree--all in the X plane, with little or no other component to the collision. This is the kind of collision that a car is designed for.

In the case of our ill-fated BWW, however, it would have struck the tree at an angle:



...at 70 MPH in one direction, 43 in another. On the roof.

But, what the hell. Dead is dead.

* * *

I am interested to learn that the morons may have been drag racing. Interested, but not terribly surprised.

I see, all the time on Pennock's Fiero Forum, people who argue that as long as street racers don't endanger others, they should be allowed to do whatever they want to.

Here is an example of what happens, though, when street racing is taken to a "safe" venue: people still end up dying.

It's obvious that the driver of the 2008 BMW in question did not know how to drive his car at that end of its performance envelope; and in fact I'd question his ability to comprehend that "faster speed" means "it's going to take longer for you to stop". God alone knows what his speed was before he started braking; but physics tells me that he was going 70 when he left the runway, and it's no stretch for any modern production car to break 100 MPH. In all probability his speed was somewhere north of 130 when he started braking. He couldn't stop fast enough, went off the end, and the rest is history.

This is why the people who find "deserted roads" to street race aren't any better--nor any smarter--than the morons who do it in populated areas.

When you race at a track, the people who run the race are there to help you minimize the risks you are taking. They have no emotional involvement in your success or failure as a racer; all they care about is making sure that you have an environment in which you can "go that way, really fast" without putting anyone else or yourself in any more danger than is strictly necessary. They do this by requiring certain amounts of safety equipment and by holding the race in an environment specifically designed for it.

So that if you do lose control of your car, you don't hit a light pole or a tree, but a safety barrier which is designed to extend the duration of impact as long as possible, in order to reduce the forces you experience. Lowering acceleration.

The environment also has plenty of visual cues for the driver to let him know when he is running out of room; and many drag strips have a "sand pit" at the far end, where an out-of-control car gets bogged down in loose sand.

A deserted road--or landing strip--has none of this.

In the end, regardless of the particulars, an age-old equation has again been satisfied: youth plus stupidity plus speed equals dead bodies.

#860: It's news time again!

Well, news and commentary. You know the drill.

Not an overdose? Heath Ledger, healthy young man, aged 28, had a "heart attack". Yeah. That's what killed him--a heart attack. Okay.

What I like best about this article, though, is them mention of Robert Red-ford: "At the Sundance Film Festival in Utah, Robert Redford, the veteran actor, talked about the impact of Ledger's death, comparing it to the shock caused by the 1981 assassination attempt on Ronald Reagan."

A "shock"? Red-ford was probably dancing and singing when he heard about the attack on Reagan.

Heavy-handed, top-down management at Hillary Central. Why is this a surprise? How can there be anyone in the US of voting age who doesn't know how Hillary Clinton does things? Those of us who put up with the last Clinton administration remember all to well what she was like. For example, it was never enough just to fire someone; they had to destroy him. (White House Travel Office, anyone?) This is how the Clintons do things. Vote for it at your own peril.

Vox Day's book apparently is a refutation of the religion of atheism. I'm not sure I want to wade through the article in search of quotations, which probably means I won't buy the book, either--but hopefully it'll twist a few nipples on that side of the aisle.

Bill Clinton's best-known victim writes an open letter to B. Hussein Obama about how nasty the Clintons can get. (They can get pretty bad.) This is someone who is speaking from personal experience, mind you.

I live in Obama's state and this is the first I've heard about this crap. Obama's pastor sez "In the 21st century, white America got a wake-up call after 9/11/01. White America and the Western world came to realize that people of color had not gone away, faded into the woodwork or just 'disappeared,' as the Great White West kept on its merry way of ignoring Black concerns."

And: "Minister Farrakhan will be remembered as one of the 20th and 21st century giants of the African-American religious experience."

And the quote that begat the article: "Black women are being raped daily in Darfur, Sudan, in the Congo and in Sub-Saharan Africa. That doesn't make news. One 18-year-old white girl from Alabama gets drunk on a graduation trip to Aruba, goes off and 'gives it up' while in a foreign country, and that stays in the news for months! Maybe I am missing something!"

The funny quote: "For his commitment to truth, education and leadership, we honor Minister Louis Farrakhan with the Rev. Dr. Jeremiah A. Wright Jr. Lifetime Achievement Award." That's right: Obama's pastor gave Farrakhan an award named after himself. That's hilarious.

Maybe I should do that. Start handing out the "Ed Hering Lifetime Achievement Award" to people who deserve it. That would be cool.

Please do this. It would be so amazingly funny to see them do this.

President: "Hi, I'm George Bush!"
Vermont law enforcement official: "Mr. President, we're arresting you for [crimes]."
Secret Service: "Put those cuffs away or get shot."

Why? "Daims said the most grievous crime committed by Bush and Cheney was perjury — lying to Congress and U.S. citizens about the basis of a war in Iraq."

It's clear that the originator of this stupidity doesn't understand the meaning of the word of "perjury". He's obviously just regurgitating stuff he heard online and during the Clinton impeachment.

See, it's not "perjury" to lie to Congress. If it were, we'd be arresting all the congresscritters too. It's also not "perjury" to lie to the American people. If it were, all our politicians, reporters, and entertainers would be doing their jobs from prison.

"Perjury" occurs when you lie under oath, such as when Bill Clinton lied while giving his deposition for the Paula Jones lawsuit. When you give a deposition, you're under oath, and he lied about having sex with Monica Lewinsky. He committed perjury.

And in order for there to be "perjury" there must be a lie. The "shout at the wind" moment for today is that when everyone's best information says "A", so you say "A", and "B" later turns out to be the case, it is not a lie. If everyone's best information says "B", but you say "A"--and then "B" is later shown to be correct--that is a lie.

All the intelligence agencies that the US trades info with said the same thing: "Saddam has WMDs". This was a "best estimate". Saddam knew we were coming, and in the months running up to our invasion of Iraq there was a world-wide shortage of shipping containers. Then we get into Iraq and--hey, no WMDs? WTF? This is why Bush didn't lie: he shared information which he believed to be true, which all the experts said was correct. That that information later turned out to be incorrect does not retroactively make what he said a lie.

The moron responsible for this tripe goes on to regurgitate all the other Moron.org MoveOn.orgtalking points: Bush spied on the American people, 600,000 people died in Iraq, obstruction of justice, and "politically motivated firings of US attorneys".

That last is a laugh, too: is he going after Bill Clinton for firing all the US attorneys when he was in office? Bush only fired eight of 'em; Clinton sacked every last one. If that's an arrestable offense this douchebag ought to be after Clinton, too.

...of course, those attorneys serve at the pleasure of the President. The President can fire them at any time for any reason and replace them with whomever they want.

Thee comments for this article are fun to read, too.

#861: Wake me when ef--a tale of memories is over.

I just finished watching episode 7 of that series (F) and good lord is it tedious.

I can almost excuse the "art student" animation of the latter half of the episode, but when I find myself yelling at the TV, "Okay, WE GET IT, MOVE ON ALREADY!" it's obviously crossed a line that shouldn't have been crossed.

Miyako is going on a date with Hiro, but Hiro is standing her up because his childhood friend Kei hurt herself while playing basketball, and he's helping her. He also left his cellphone at home.

So Miyako, waiting for him at their rendesvous point, keeps calling and calling and calling him, with increasingly desperate messages. And the producers of this stuff WAY OVERDID this bit. They went beyond tedium into "STFU FOR CHRIST'S SAKE YOU WHINY BITCH" territory.

This is after, by the way, they over-animated a sequence between Renji and Chihiro, too. O Gawd did they over-animate that crap. Real people don't move like that. They just don't.

Kei--who formerly had declared war on Miyako, and said she'd erase her from Hiro's heart--erased all her messages before Hiro-kun had a chance to hear them. To be honest, I was glad; not just because I don't particularly like Miyako, but because after all that BS with the text of her messages appearing on the screen and no other animation whatsoever for SIX FREAKING MINUTES, I want her to disappear.

From the scene with the phone messages, right to end credits--then a little extra afterwards showing Kei deleting the messages. Finally a scene with real animation and decent pacing. Without that, the entire last thirteen minutes of the episode would have been utter shit.

So far this series has alternated between "really good" and "God-awful". The last half of ep 7 is of the latter category; in fact it's the worst that this show has been so far. Good God, what a mess.