How hard was Felipe Massa hit, exactly? | Hacker News Reader

How hard was Felipe Massa hit, exactly?

f1fanatic.co.uk

41 pointskarzeem20 comments

These calculation are correct, but the wrong ones to use.

It's not energy that causes injuries, it's force. But force is much much more difficult to calculate. You need to know the area of the impact, and even harder is calculating how long the deceleration takes.

The helmet spreads out the area so that it's basically half of the entire head (instead of a small area). The foam inside spreads out the deceleration time. The nature of a spring would also slow down (i.e. increase) the deceleration time.

If he body moved backward as it got hit, that too would spread out the deceleration (i.e. move it from his head/brain, into his entire body).

I remember seeing a video that talked about the physics of boxing, specifically rolling with the punches. It clearly works, people who roll are hit much less hard.

However, a champion boxer hits at ~90MPH. You can't jerk yourself back fast enough to make an appriciable dent on the KE of the punch. The effect is almost all in the dt of F=dp/dt.

There are a whole bunch of tough-to-avoid assumptions which make the 2046 joules likely to be imprecise. And in any case, as you say, force is ultimately the relevant issue. The article is meant more to put the impact into perspective by comparing it with familiar projectiles, and not so much as an objective modeling of the impact.

Edit: by way of full disclosure, I wrote the article.

Energy is the integral of force times distance (uh, dot-product there: ∫F⃗·dx⃗, where x⃗ is position). The distance should be pretty easy to put bounds on: no substantial force was being applied to the spring until it made contact with the helmet, and after that it, and the helmet, and the driver, deformed until the energy of the impact was transferred into some form other than the kinetic energy of the spring moving into the helmet. That lets you put a lower bound on the force. (Of course it doesn't allow you to put an upper bound on it.)

I really like the conclusion, about not waiting for a death to realize what can happen.

The thing is that it is not the open cockpit that can kill, it is the speed. And the speed is why this sport has so many fans.

Also remember that apart from being hit in his head Massa also hit a wall of tires at 200+ kph. I know they were there to absorb the shock, still, try doing that in a regular car...

speed does not kill, it's acceleration (o rather deceleration ) that does :)

acceleration does not kill either, it's variance inside the body that does (a free fall in a strong but relatively uniform gravitational field does no harm e.g., a cosmonaut on the international space station).

Yes, uniform acceleration under gravity is equivalent to remaining still!

http://en.wikipedia.org/wiki/Universality_of_free_fall#The_E...

"...Massa also hit a wall of tires at 200+ kph. I know they were there to absorb the shock, still, try doing that in a regular car..."

Is a Formula 1 car any better in an impact than a modern car with, say, 5 Euro NCAP stars[1]? I had a quick Google and it seems that the most important safety feature in this situation is the head and neck support system:

"The leading causes of death in auto racing accidents are skull and neck fractures resulting from rapid deceleration during accidents. The Head and Neck Support system (HANS) was designed to reduce these whiplash effects. The system consists of a collar that is attached to the safety belt and strapped to the helmet to hold the helmet in place during an accident. HANS usage became mandatory in Formula One racing in 2003." [2]

[1] http://en.wikipedia.org/wiki/Euro_NCAP

[2] http://wiki.answers.com/Q/What_are_the_three_main_safety_fea...

Yes, F1 cars are designed to survive (or rather the driver to survive) even 300kph accidents. They are safer than 5* EURONCAP in this sense. Things to note are:

a) F1 drivers are very fit as opposed to regular people (so they can endure damage more easily)

b) you wouldn't want to drive an F1 on the street because of other safety issues

You should look up the monocoque F1-cars use. They basically are a carbon case just around the driver which is designed to hodl of ridiculous forces from just about any direction. One can go as far as saying: there is pretty much no chance in hell that a F1-driver is somewhat crushed inside this monocoque. So, the F1-cars are damn secure, and I do mean damn secure and while it is true that there are some fairly ugly accidents out there in the F1-world, one has to keep in mind: that is a car travelling at 200+kph and hits a wall. In about any other car, the driver would be dead. So, keep in mind: security in F1 is something else (Survive!) as security in regular street cars (get out of there without injuries).

cp eg here: http://www.formula1.com/inside_f1/understanding_the_sport/52...

There are no cockpit covers it allows the driver to get out (or removed by marshalls) quickly in case of fire (which was the biggest in old days).

yeah these days, risk of fire is quite less but still its a delicate balance which one has is more risky (fire or debris hitting drivers)

One detail: according to Martin Brundle, the BBC commentator, it was more like 60mph (100kph). When Massa was knocked unconscious by the spring, his feet came to rest on the accelerator and brake - both were down when he went into the wall.

It was a terrifying accident.

What was ignored here is that springs are specifically designed to absorb kinetic energy, or more specifically, the spring would tend to spread the energy of the impact out over a longer period of time due to compression. (Much like the tyre wall that Masa slammed into seconds later).

This would obviously depend a lot on the orientation of the spring when it impacted the helmet, but there's a good possibility that the outcome would have been very different if he'd been hit by an object of similar mass but different geometry.

That isn't to say the impact wasn't incredible and horrific. I'm very glad that he appears to be recovering well.

... and also that the spring was not motionless at the time of impact. If you can find the video, it turns out that the car that lost the spring isn't even in sight, so the spring has had some time to decelerate. Still, it is clearly still moving (bouncing). To calculate the impact energy, you need to know the relative velocity between the spring and Massa. Also, once the back of his helmet hit the headrest, the helmet would absorb energy until it cracked, which it appeared it did not.

My guess is that more damage was done by the head-on collision with the wall than by the errant spring. These cars have cockpits specifically designed for safety, but without an airbag there isn't much to help the driver in a head on collision with no deflection. The tire wall seems to have absorbed a lot of the energy, but as the car actually penetrated the wall it may have defeated the primary head on collision safety feature, the crumple zone.

> My guess is that more damage was done by the head-on collision with the wall than by the errant spring

Given that the medical treatment Massa has received all seems to relate to head/eye trauma I think it's pretty safe to say it's the spring that did the damage. Kovalainen's impact into the tires last year was similar and he pretty much walked away from that.

> but without an airbag there isn't much to help the driver in a head on collision with no deflection

That's specifically what the HANS device is for, it's a huge amount of help in that situation.

I'm not so sure that made a difference. Springs are designed to store energy that is delivered by a force from a specific direction If I hit you in the face with the side of a coil spring vs. in the direction of the coil, the amount of energy the spring will store (and thus how badly you are injured) is vastly different.

Which is why I said: "This would obviously depend a lot on the orientation of the spring when it impacted the helmet".

I haven't lost a race in the last 6 years and I must say this is freakiest accident I've seen by far.

Ruben's lost a spring on his car, and it ended up in Massa's helmet. What the chances of that?

The injury was due to the spring (although the crash didn't help)

If anyone wants to see a demonstration of how F1 car is safe have a look at this: http://www.youtube.com/watch?v=MZqBbLyp6oo Kubica was pretty much on his legs the same day.

Here's a pic showing the damage to Massa's helmet and eye http://static1.buenosairesherald.com/media/news/images/desta...

The teams are all very concerned about safety and I expect much stronger helmets and visors in the near future. The fact that he walked away without any broken bones is a testament to the excellent quality of modern F1 safety cells protecting the drivers. Unfortunately this accident could still be the end of Massa's career due to the damage to his eye socket.

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