BXProject

Is a 50mph Head on crash the same as 1 car hitting a wall at 100mph?

Well, if like me you like to see cars being mashed to crap have a looky...

http://www.youtube.com/watch?v=c-JGIYLZZUg

Try and ignore the annoying OTT american comentary...

Interesting, as we always think about closing speeds.

So their tests and theory is for two identical cars of equal mass.

Where the masses are unequal, which car then comes off worse?

Yeah, and stuff but when cars collide head on they never quite do hit head on and are usually of unequal mass, so the data can only be used as a reference point

The ONLY point of the test was to dispell the myth.

Is a 50mph Head on crash the same as 1 car hitting a wall at 100mph?

And the test answers the question perfectly.

It wasn't intended to provide or present any other conclusion or evidence. The use of identical cars only proves the theory moreso, whereas cars of different mass would not have answered the question...

I do agree with w2g's query tho: "Where the masses are unequal, which car then comes off worse?". In normal theory one would say the heavier car would win, but you then have to consider crumple zones etc... Mythbusters use of identical cars meant these considerations were not necessary.

That head on crash test between an old Volvosaurus estate and a Renault Modus (5th Gear?) gave interesting results. Which do you think came off worse?

Mark.

I’ve seen that one too – I’m pretty sure it will be on 5th Gear’s YouTube channel. Being the cynic that I am I can’t help wondering that (as it is in the motoring media’s interest to have a healthy new car industry) whether the tests are entirely fair. All you would need to do to significantly skew the results is find an older car with a bit of structural corrosion in the ‘right’ places…
I don’t doubt that newer cars are generally safer in a crash situation, but wonder if the difference is as marked as these sorts of things would suggest. And that’s leaving aside the size of the blind spot behind those nice thick, airbag protected windscreen pillars.

mat_the_cat wrote:I don’t doubt that newer cars are generally safer in a crash situation, but wonder if the difference is as marked as these sorts of things would suggest. And that’s leaving aside the size of the blind spot behind those nice thick, airbag protected windscreen pillars.

It's amazing how often old-car-drivers bring this up. I very rarely drive modern cars, but I feel blind when I do - and I can't wait to get back to my nice, safe BX where I know what's going on all around me (estates much better than hatches in this respect, incidentally!)

I find similar going between the BX and the bike - greater vulnerability, but (partly) balanced by greater awareness.

Well I will be going between the Picasso, which has large said pillars, ( which you actually get used to pretty quick due to the enormous glass area) the BX and the B40. So I'll record my feelings then.

It's obvious if you know anything about phsyics really.... kinetic energy is proportional to velocity squared. So total energy of 2 cars at 50mph is 2 x mass x 50² = 500m. 1 car at 100mph = mass x 100² = 1000m ie twice the energy. The equivalent speed would be root 2 times 50 which is about 70mph (70 squared being 490).

Sad git mode off

Ah yes but that only works with a given cube shaped and evenly distributed mass. The shape and distribution of a vehicle presents a further equation.

Thus M 1 = [M/2 root rad 4m+M/4x502]x500 going into a stationary wall.
To calculate the resultant force at 100 merely do the same equation to give a value of M in Newton meters.

That is all.

The presenters were very annoying. But point proven.

And a big car will always mash a small one; s'physics, innit?

I must have been a weird kid, when I got knocked off my bike by a bloke in a Lada, I told everyone it was a Jaguar

But they will know you lied. If you had been hit by a Jag you would have been ded.

The Lada, on the other hand, collapsed on impact...Obviously

I told the church choir - so they were already susceptible to believing fairy stories

I've heard tales about people that tell fairy stories to choristers

I was expelled anyway - the last straw was when I went a bit mad in the middle of a wedding because a spider was attacking me.

We used to get paid 4p for a Sunday service and 20p for a wedding (mid 70's) - I just liked the music.

That's a lot more than we got during the 50's. We got a whole sixpence for a wedding or a funeral and nothing for sunday morning and evening services, or practice for 2 hours mon and thur evenings.
But I did get to sing solo with the Halle orchestra, conducted by sir adrian bolt. That was cool.
We always got to sing a lot of medieval stuff too, which I still enjoy

Philhod wrote:We always got to sing a lot of medieval stuff too, which I still enjoy

Crikey Phil, I knew you were old but I thought you grew up after medievel times!

You are aware Mat, that I am one of the immortals?

I thought you knew that