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Comment by krschultz | Hacker News Reader

K=1/2*mv^2?

My intuition (as a mechanical engineer, desinging military systems as my day job) is that the F16 going supersonic is far worse. Either way, there is no possible way you have enough information to make any of the claims you just made.

A better question to ask yourself how safe your highway transportation is, because within an hour of my house we've had 15 people killed in bus accidents in the last 72 hours. And that doesn't even begin to count car accidents. I live within 5 miles of over 10 nuclear reactors and they have never and will never scare me because I actually understand the engineering behind them. Nuclear power is not magic. Small doses of radiation scare me far less than the concussions I get from sports I play.

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> Either way, there is no possible way you have enough information to make any of the claims you just made.

I took out this from this report (http://www.euronuclear.org/reflections/nuclear-facilities.ht...), which I think was also mentioned by jgrahamc:

> The studies showed that even if knowledgeable insiders could disable key safety equipment, redundant systems would provide backup protection. In scenarios where all engineered safety systems were ruined, there was still a period of hours to take corrective actions before onset of core damage.

Now, you may argue that what indeed went wrong in the case of the Fukushima plant was that the "redundant systems" didn't provide the "backup protection" the experts relied on. I see this report is confident this would not be the case were the terrorists to hit a nuclear plant, but based on what happened in the last few days I'd say the confidence level for that scenario is bellow 100%.

Anyway, thx for those downvotting me, and I hope I'll never be proven right.

The backup generators that they bought on site had the wrong types of plugs on them.

When this is all done, I am sure that most of the problems at Fukishima will be found to be administrative rather than design.

As an aside, that plant was designed to withstand an 8.4 earthquake. Design requirements and actual strength are two different issues. Even a complete meltdown, such as at Three Mile Island, should be contained.

'had the wrong types of plugs on them'

I have seen this as one of the biggest failures so far.

Huh? The mass of the A380 is at least 100 (and perhaps 1000) times the mass of the F16 (just picture them flying side-by-side and note the area of sky obscured by the A380 versus the F16 and note that although the mass density of the F16 might be higher than the A380 because much more of the mass is engine, it is not twice as dense as the A380).

And no way can the F16 go 10 times as fast as the A380.

So the kinetic energy of the A380 is definitely higher, probably by a considerable amount.

Weight (Maximum take off)

  A380 = 569000 kg [1]

  F-16 = 19200 kg [2]

Top Speed

  A380 = 945 km/h = 262.5 m / s

  F-16 =  2410 km/h = 669.444444 m / s

Kinetic Energy

  E = 0.5 * m * (v^2)

  E380 = 0.5 * 569000* (262.5^2) = 19 603 828 125

  EF16 = 0.5 * 19200 * (669.444444^2) = 4.30229629 × 10^9

[1] http://en.wikipedia.org/wiki/A380

[2] http://en.wikipedia.org/wiki/F-16_Fighting_Falcon

That said I think it probably doesn't matter. On impact the plane would breakup and you probably wouldn't get full force from either and also I bet it was built with more then a factor of 10 safety factor.

My intuition says you are wrong. But I am just a person who liked his high school physics class 10 years ago.

http://en.wikipedia.org/wiki/Airbus_A380

http://en.wikipedia.org/wiki/General_Dynamics_F-16_Fighting_...

A380 typical operating weight: 600,000 lb

F16 Loaded weight: 26,500 lb

A380 Max Speed: 580 MPH

F 16 Max Speed: 1500 MPH

Airbus weight advantage ~= factor of 30

F 16 speed advantage ~= factor of 3

3 ^ 2 < 30

Maybe there is some destructive value in having the kinetic energy more concentrated in the F16, but a full speed A380 has a lot more kinetic energy than a full speed F16.

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