Dang, Corvettes a lot safer than I thought...

[pgardn]

It does not matter. The delta-v is measure of collision severity and a surrogate measure for injury potential.

Collision duration is typically around 120 msec. I suspect slightly longer for this crash.

It does to matter if you want acceleration.
You cannot get acceleration directly from the conservation of momentum. It has to be delta V/ time, or F =ma (F/m = a)
Thats what I requested.
You already gave me an incorrect equation.

Thanks for the time, Why do you suspect longer?

[DarrinS]

It does to matter if you want acceleration.
Thats what I requested.
You already gave me an incorrect equation.

Why do you suspect longer?

I gave you no incorrect equation.

I suspect longer duration because partial underride.


If I had the EDR data, I could give you the amt of time. About where DV time series hits plateau.






At the end of the day, accident reconstructionists use delta-v, not acceleration.

[SnakeBoy]

Ruggs and the car he hit were going in the same direction. You can estimate the speed of the car he hit by looking at the speed limit sign in the picture below.

Can you use other clues from the picture to triangulate the location?

[pgardn]

friction

M1 * DV1 = M2 * DV2

No time in this eq.

IN ENGLISH, what do each of these symbols stand for.
I assume 1 and 2 represent the two different cars.

[hater]

Well Im glad Corvettes and the drunk bas s that drive them are safe.


Rav4s are damn safe cars so that pig of a human must have hit it at abive 150mph

They should chop that.bas s.legs. at a minimum

Niga thought he was playing Rocket League smh

[DarrinS]

IN ENGLISH, what do each of these symbols stand for.
I assume 1 and 2 represent the two different cars.

M = mass
V = velocity
1,2 = vehicle number
a = after crash
b = before crash

M1*V1a + M2*V2a = M1*V1b + M2*V2b

Momentum after = Momentum before

M1 (V1a - V1b) = M2 (V2a - V2b)

M1 * DV1 = M2 * DV2

Change in momentum for vehicle 1 = Change in momentum for vehicle 2

[SnakeBoy]

How did such a benign thread turn into an argument so quickly

Newton's third law

[Winehole23]

but people have died even when airbags have gone off so stop pretending they can prevent death

same deal with bulletproof vests, they don't prevent you 100% from getting shot, why are they worn at all?

[hater]

I just learned that airbags are really borderline improvement in fatal car crashes tbqh. Statistically they have saved a small # of ppl. Seat belts on the other hand are a crucial lifesaver.

Also too many variables in car crashes. Look at Tiger Woods. Dude survived I believe he hit a tree at 180mph? But was extremely lucky at the angle. A few more degrees.and that mofo would be playing golf with Kobe, Mccain, Powell and the Cenobites.

[CosmicCowboy]

Tiger wasn't going 180.

[hater]

Tiger wasn't going 180.

Haha meant 80mph. Butbactuly says almost 90.

My point stands.

[DarrinS]

This is why simple physics equations doesn't work. Was all the force of one car going against the force of another car? Probably not ...

[DarrinS]

Not only was he drunk and speeding, but evidently, he also violated Newton's third law.

[DMC]

Or, they can read the event data recorder. Durrr

Also, striking a barrier is a lot different than striking another vehicle.

Maybe don't pretend to be an expert on everything, RG.


Lol, using the speed limit sign.

RG really tries hard to sell the notion that he's educated but even a simple glance at his posts makes it abundantly obvious he's a Google regurgitation machine in the mold of Wild Cobra. Just like that *snap* he has the answer.. just like that.

[DMC]

This is exactly the point he was trying to make I thought?
Ruggs would be absolutely dead if it had been a barrier.

And the speed limit sign is a good way of "approximating" the speed the OTHER car was going.
Whats wrong with this?

So an airbag control module is the same as an event recording device. What was the avg. acceleration of both cars during the collision?
I would like to know just for the of it.

Apply that to both vehicles

[DMC]

Not only was he drunk and speeding, but evidently, he also violated Newton's third law.

It's a discriminatory law anyhow

[DMC]

This is why simple physics equations doesn't work. Was all the force of one car going against the force of another car? Probably not (due to angle of impact and crumple of car distributing energy in weird ways). So that throws away all of y'alls stupid equations. We need to apply drag, friction, maybe more forces. Physics problems are not real life (ex. frictionless rope). That should be the first thing you get out of physics.

Ain't you got a bomb to diffuse? Get after it son.

[pgardn]

M = mass
V = velocity
1,2 = vehicle number
a = after crash
b = before crash

M1*V1a + M2*V2a = M1*V1b + M2*V2b

Momentum after = Momentum before

M1 (V1a - V1b) = M2 (V2a - V2b)

M1 * DV1 = M2 * DV2

Change in momentum for vehicle 1 = Change in momentum for vehicle 2

Yep.
Thanks.

[pgardn]

Apply that to both vehicles

Why ?
when you have the info on the corvette?

[pgardn]

I gave you no incorrect equation.

I suspect longer duration because partial underride.


If I had the EDR data, I could give you the amt of time. About where DV time series hits plateau.






At the end of the day, accident reconstructionists use delta-v, not acceleration.

Uhhh darrin...

Do you know what the SLOPE of that line is?
Now you might understand DV/Dt = guess what????
You put up a V/t graph... did you realize this? Its versus TIME, t...

All I wanted was a "feeling" for the acceleration the occupants might have percieved.
And just to be complete. "We" need to decide which units to use. Since in the English system ft/sec/sec is accepted for the standard, and g = 32 ft/ sec/sec, guess what? You can represent the acceleration in g's, which is very OFTEN used to make this understandable to the general public. One can actually just lie on the floor and fell the pressing, the force of gravity (actually the normal force back on you). And then you know its like feeling 1g of acceleration without actually accelerating because the floor must be pushing back on you with the same force as gravity pulls you down.

People can understand this a bit better.
So from your graph, WHICH HAS TIME, how many g's did the occupants feel? Even though this does not have the correct speeds and looks closer to a ~90 msec impact. You must have time of the impact (when the cars are in contanct) to get an idea of what accelerations they might have felt.

[pgardn]

How did such a benign thread turn into an argument so quickly

RG bashing by people who might need a bashing as well.

[CosmicCowboy]

how many g's did the occupants feel?

Don't know how many G's they felt but they apparently felt about 1500 F's.

[pgardn]

It does not matter. The delta-v is measure of collision severity and a surrogate measure for injury potential.

Collision duration is typically around 120 msec. I suspect slightly longer for this crash.

Delta v on its own means absolutely nothing.
There are barriers on the highway that serve to bring your speed from very high to zero. These are COLLISIONS. These barriers are designed to change the impulse to the car. They serve to make the Force on the car less and the TIME longer and cause exactly the same change in momentum and give you exactly the same delta V.

Its totally ridiculous to only use change in V. It means nothing alone and without a given amount of time. Its totally ridiculous. You can have a car going 100 mph and come to a complete stop over a 10 sec time period. So the delta V is 100. Then have the same delta V over 0.1 seconds. This results in a force 100 X different on the car. These two different times are essential. Thats why barriers that do not "give" are not good to run into. The stop you very quickly with a very large force.

[Trainwreck2100]

Rigg's air bags went off at 127mph when it blew up the Rav4 and he and his girlfriend both walked away. Thats crazy.

it didnt blow up the rav4, apparently the fire started small but because they couldn't get her out she burned alive. If he hits anything that wasn't a vehicle with elevation he's probably dead as well

[pgardn]

This is why simple physics equations doesn't work. Was all the force of one car going against the force of another car? Probably not (due to angle of impact and crumple of car distributing energy in weird ways). So that throws away all of y'alls stupid equations. We need to apply drag, friction, maybe more forces. Physics problems are not real life (ex. frictionless rope). That should be the first thing you get out of physics.

This is true there are lots of variables but we can get a ball park estimation of the kind of forces and accelerations produced on the occupants.
And this can give you a better feeling for the types of anatomically damage people will get. I mean you could theoretically put some one on a jet sled start them at 160 mph and bring them to a stop in a short time to see if their eyes pop out. But the actual wrecks help with safety to the anatomy. And they tell the car manufacturers to create "crunch zones" in the car itself that help to dissipate the energy or in other words, act exactly like an air bag or padding would built into the structure of the car. None of it is ever perfect but we have done a pretty amazing jobs at making high speed crashes not result in death. This was a good example from CC.