Anyone see the 5th gear car crash?

didnt find it shocking at all to be honest, and im not sure why others have, what do you expect to happen to a light weight metal shell made of pressed sheet steel less than a mm thick?
 
you could build a cage much more capable of withstanding the impact quite easily, get rid of the crumple zones, or make them much tougher, and have a pasneger compartment that was pretty intact after the crash, but there would be no point. the deacceleration would have turned your internal organs to mush and killed you instantly anyway, and would do so at much slower speeds as well.
 
better to have cars that survive lowish speed impacts much better AND more importantly provide controlled deacceleration for the pasengers.  those impacts are much more common, and survivable.   these types of crashes wouldnt be, no matter how strong you made the car, unless it was 30 foot long with a mega crumple zone and strong passenger cell to give the best of both worlds.

I agree Daz, its no shock that happens to the car - its basic physics. I do however find it quite chilling, sobering if you like to see the potential effects of speeding like that... and yes I know thats never quite likely to happen and the speed is daft too.
 
fools speed  

Christ. 
gonna tell the kids to belt up when coming home from the pub

RobW


I don't see the point of the test?

I mean seriously how many 3 m thick solid concrete walls are there out there??

The supports on every motorway bridge you drive under...

j55ttc


Youre right, its all to do with momentum and mass.

If you're going 60 mph and you pass someone in the next lane going 60 mph, it will appear that you will pass them at 120 mph.

However, when talking about collisions, it's all about the momentum. If a cargo van going 60 mph hits a smart car going 60 mph head on, they won't feel the same thing. Obviously the smart car will lose. This is because momentum must be conserved first, then velocity can be calculated.

So let's associate mass with the vehicles. The cargo van weighs 10,000 kg and the smart car weighs 1,000 kg. When the collision occurs at those speeds, the cargo van will have 600,000 kgm/s of momentum while the smart car has only 60,000 kgm/s of momentum. At the moment of the collision, the momentum will become the larger momentum (600,000 kgm/s) minus the smaller momentum (60,000 kgm/s). We can do this calculation because the collision is head on and has 1 dimensional vector quantities, meaning that we do the calculation in a straight line. So the total momentum of the system will become 540,000 kgm/s in the direction of the cargo van, because it had the larger original momentum. If those two cars were to stick together and move off in the same direction, we can find the velocity by dividing the new momentum by the sum of the masses (10,000 kg + 1,000 kg = 11,000 kg). This turns out to be roughly 50 mph. (540,000/11,000=49.0909...) Using that information, you can figure out about the speed that the car would hit the wall to achieve the same force. If we start with the cargo van, it started out going 60 mph and ended going 50 mph in the same direction. If you subtract the two, it's similar to if that van were to hit a wall going 10 mph. As for the smart car, it started at 60 mph and ended at 50 mph in the opposite direction. Meaning it might as well have hit a wall going 110 mph.

Thats actually a really interesting post - I didnt understand the physics of it before. So the end result actually isnt what 'common sense' would suggest...
 
I'll try and remember that if I ever hot a truck head on in my little fiesta... in the micro seconds before my my spine exits via the top of my skull...  lol!
 
 

Interesting problem to model mathematically.
 

Im assuming it would be quite difficult to model accurately? So many minor factors to be considered - exact angle of impact, precise crumple zone parameters of the vehicles involved etc - im thinking 'butterfly effect' where tiny variations in original comditions in a complex model can produce widely varying end results - or would these make only the most minor of differences, and the basic end results can be modelled easily from relative mass/velocity of the vehicles?
 
Is a car crash a 'complex system', or a fairly basic equation ?

It would be very difficult to model on paper as a system, if not impossible.
Fairly easy as a particle and we can start by modelling it in one dimension - with no sideways or upways acceleration or momentum.
I'm far from convinced that smacking it into a concrete slab is an accurate way of modelling dual-120mph impact between two cars - regardless of thoughts in this thread about linear momentum, normal forces, etc.
It would be interesting, to me, to attempt to model it in an elementary sense, however.
 

rightyho


It would be very difficult to model on paper as a system, if not impossible.
Fairly easy as a particle and we can start by modelling it in one dimension - with no sideways or upways acceleration or momentum.
I'm far from convinced that smacking it into a concrete slab is an accurate way of modelling dual-120mph impact between two cars - regardless of thoughts in this thread about linear momentum, normal forces, etc.
It would be interesting, to me, to attempt to model it in an elementary sense, however.

Im thinking (bearing in mind that Im no kind of mathematician/physicist at all), that one significant difference between a vehicle and a concrete block would be the downward forces in the second dimension (traction) - a concrete block fixed to the floor will have no tendency at all to disperse kinetic energy through upward movement - whereas, as can be seen on the video, the car exhibits a significant degree of 'lift' off the road surface (and subsequent dumping on whats left of its front!) and presumeably the energy required to lift the mass of the car off the road  would have to be subtracted from the amount of energy passing horizontally through the body of the vehicle? With the concrete block (as opposed to another vehicle) this effects only ONE of the objects, not both.
 
Or is energy also displaced vertically through the block in a (failed) attempt to lift it?
 
also with no 'crumple zone' in the block then again presumeably energy isnt being used to distort the structure in the way it does with another vehicle?

jeffhead


Christ. 
gonna tell the kids to belt up when coming home from the pub

 
This will keep them in the smashed vehicle!
 
 Many moons ago i  had a smash at 100 miles and hour,(actually it was 97 miles an hour) but close enough,i hit a lamp post in huddersfield,put a town out of electricity for 2 days,my name is eched on the new lamp post and the date.
 
I was thrown clear through the front wondow and into a field,i broke my right arm in 3 places,my left leg in 2 places and recieved many deep scratches.my brother was sat in the back,and stayed in the vehicle,he had to be cut free from a 2 foot square place in the bottom of the vehicle.
 
Had i been wearing a seatbelt,there is no doubt i would be dead,non whatsoever.
 
My point is that wearing seatbelts is not all its meant to be,i would argue in many accidents wearing a seatbelt,actually causes you more harm than good.imo of course.

ginasmg

jeffhead


Christ. 
gonna tell the kids to belt up when coming home from the pub

This will keep them in the smashed vehicle!

Many moons ago i  had a smash at 100 miles and hour,(actually it was 97 miles an hour) but close enough,i hit a lamp post in huddersfield,put a town out of electricity for 2 days,my name is eched on the new lamp post and the date.

I was thrown clear through the front wondow and into a field,i broke my right arm in 3 places,my left leg in 2 places and recieved many deep scratches.my brother was sat in the back,and stayed in the vehicle,he had to be cut free from a 2 foot square place in the bottom of the vehicle.

Had i been wearing a seatbelt,there is no doubt i would be dead,non whatsoever.

My point is that wearing seatbelts is not all its meant to be,i would argue in many accidents wearing a seatbelt,actually causes you more harm than good.imo of course.

Your 'guardian angel' must have been putting in some serious overtime that day mate!
 
Actually I know a guy who rolled an old style Mini, may years ago, and the seatbelt jammed trapping him in the car - with petrol p*ssing in to the compartment from a ruptured tank, and sparks flying from a smashed dashboard...  someone turned up and got him out by cutting the belt before the car went up in flames (thank god)... but he's refused to wear a seat belt ever since, and has been fined by the police for it on several occasions

Yes Tac someone somwhere was looking after me on that occasion.
 
I take your point on the belts,i dont like wearing one myself (as dont millions of others) probably in accidents involving lower speed they might save some injuries.
 
But at higher speeds i would say they can be a hindrance,and cause more damage than good.

I think I was working there when 5th gear were setting that test up as I work on the havoc site at MIRA quite a bit.  Seeing tests like that in person is 100000 times better lol

tac

rightyho


It would be very difficult to model on paper as a system, if not impossible.
Fairly easy as a particle and we can start by modelling it in one dimension - with no sideways or upways acceleration or momentum.
I'm far from convinced that smacking it into a concrete slab is an accurate way of modelling dual-120mph impact between two cars - regardless of thoughts in this thread about linear momentum, normal forces, etc.
It would be interesting, to me, to attempt to model it in an elementary sense, however.

Im thinking (bearing in mind that Im no kind of mathematician/physicist at all), that one significant difference between a vehicle and a concrete block would be the downward forces in the second dimension (traction) - a concrete block fixed to the floor will have no tendency at all to disperse kinetic energy through upward movement - whereas, as can be seen on the video, the car exhibits a significant degree of 'lift' off the road surface (and subsequent dumping on whats left of its front!) and presumeably the energy required to lift the mass of the car off the road  would have to be subtracted from the amount of energy passing horizontally through the body of the vehicle? With the concrete block (as opposed to another vehicle) this effects only ONE of the objects, not both.

Or is energy also displaced vertically through the block in a (failed) attempt to lift it?

also with no 'crumple zone' in the block then again presumeably energy isnt being used to distort the structure in the way it does with another vehicle?

I'll get back to you on that, mate.

Fifth gear did a test similar in the past and it was more realistic.
 

Dear me,that one was worse,one car seemed to "slice" into the other,yuk.

instantaneous death at least

Yeaman


instantaneous death at least

Thats the thing, isnt it... its an interesting debate, but however you model it, mathematically or in tests, basically if you hit another vehicle head on at 60mph you're pretty much fcuked as far as I can see...

Maths & physics aside, was anybody who drives a car really unaware of the damage that would be likely to happen to your vehicle, with you INSIDE it when you travel at speed if you were to crash into an immovable object or another vehicle coming the other way which is bigger than you?
 
If you were then i would think it's a real eye opener.

****, will defo make me think twice about going over 70 on the motorway.