Pop quiz - What is worse than an E36 driver?

[KenC]

any engineers in here able to compute the difference in force of 120mph into a wall vs 160mph into a wall?

or any one who has taken Physics 201 ;)

KE = 1/2m(v^2)

assuming the car is ~1200kg

KE for 120 = 1723776 Joules
KE for 160 = 3067350 Joules

As you can see, given the same impact (not going to calculate it), there will be nearly twice as much energy from the car traveling 160.

I actually just had a little refresher on this in one of my continuing education classes for my EMT license.

Cliff's Notes: A small increase in speed makes a pretty damn big difference in how fucked up you'll get in the crash.

[Funkmasta]

oh yea, kinetic energy. I dont think I have worked that equation since high school

[BrandC]

Because of the attitudes of many VW/Audi car owners that is why I left that community. Not only did my car make me unhappy, the community made me unhappy.

I wholeheartedly agree that he should just take it to the track. But then again you don't really have many oppurtunities to hit those speeds on most tracks/quarter miles.

But then again, I like how you linked Darwin...because it's so damn true. It will take care of itself.

[Funkmasta]

or any one who has taken Physics 201 ;)

KE = 1/2m(v^2)

assuming the car is ~1200kg

KE for 120 = 1723776 Joules
KE for 160 = 3067350 Joules

As you can see, given the same impact (not going to calculate it), there will be nearly twice as much energy from the car traveling 160.

I actually just had a little refresher on this in one of my continuing education classes for my EMT license.

Cliff's Notes: A small increase in speed makes a pretty damn big difference in how fucked up you'll get in the crash.

Anyone know how to convert 3067350 Joules into ft-lb's upon impact? :D

[dom]

an online calculator spit out:
2,262,360.8007 ft-lb's

[george graves]

an online calculator spit out:
2,262,360.8007 ft-lb's

Ummm, no. Take a physics class. You can convert linear motion into rotational, but it really makes no sence unless you are deep into the math of it.

[wRek]

How fast was he going? Your average rollcage is not too effective in a high speed accident. A 4 point or 6 point cage probably wont help you much in a 120mph crash. In fact there is a good chance the thing will either crush you or a tube will break and stab you (the break would be assuming the cage was welded by a amateur). Compare a rally car or other race cage to your average scca event cage and you'll see what it takes to make a cage high speed safe. Rally cages have the harness several feet back from the driver near the C-pillar to prevent the driver from contacting it.

He was estimated at well over 120 when the car went airborne. He launched off an enbankment, and ended up taking branches off a tree. They don't know for sure how fast he was going... But it was ENTIRELY too fast for public roads.

The cage was safe, and not built by an amateur. Everything in that car was done as close to perfect as possible.

[fwappy]

I think if I hit 165 my car would fall part.

[Axxe]

I think if I hit 165 my car would fall part.

You'd need one hell of a tailwind and a very very steep hill for that ;)

[emi325i]

an online calculator spit out:
2,262,360.8007 ft-lb's

hm.. torque isn't applicable.. just kinetic energy that can turn to heat via friction (when you brake from 160 to 0 in 1/2 miles) or destructive work when some other immovable object causes the car to decelerate from 160 to 0, in 5 feet... 5 feet = distance between bumper and the driver's head.

[Funkmasta]

I am talking about the amount of force per square inch on the wall when the car impacts ;)

[emi325i]

wow.. actually, you know what's impressive? the power required to crush a 160mph speeding car in a fraction of a second..

Power = Work/time..
Work is roughly equal to the kinetic energy, since the vehicle looses all of it in process of being crushed; at that speed everything happens so fast, so let time be 1/10s..

power = 10*Work = 10* KE = 30673500 Watts = 41,133.8411 HP

41000 Horsepower?!?!?!

[emi325i]

Even if the event took a whole second, it would still be ~4000 HP

[emi325i]

I am talking about the amount of force per square inch on the wall when the car impacts ;)

Ah, so you probably want psi.. lbs/sq inch. I have no clue how to get that

[emi325i]

power = force*speed
30673500W = force * 71.5264 m/s

force = 30673500W / 71.5264 m/s= 428841.658N = 428841.658N * 0.225 lb/N = 96,489.373 lb

that's a lot .. being hit in the head by that force... man.. that's gonna hurt