Three Car Collision. Force of Impact Calulations Needed.

I hope somebody's verdict of guilt or innocence doesn't hinge on what you find here, because this is exactly the sort of question a lawyer would ask. Contact a physicist who specialises in forensics of this sort.

There is a lot more to these sorts of problems than meets the eye. For instance, cars crush and absorb some of that impact. How, how much, and where they crush can radically alter where they end up and how fast. Slide sideways? Spin? Flip? Cars are not billiard balls. The kinetics of such collisions are very complex.

My recommendation is to search court records of cases involving similar collisions and wing it from there.

Since its is fictional

...the third car took off and rolled over impacting 6.5 m behind the incident scene. The two other cars got stuck to each other, mended by the third impact in a t-boned shape. None made it out alive but the driver from the rolled car because the driver was flung out from the open window.

btw it rolled two times mid air and came to rest on the broken wheels.

either this is a poorly veiled lie or an incredibly boorish novel.. even from an engineering standpoint.

Way WAY WAY to many details to be a novel.. Who in the world would call you out for improper details for an accident in a novel ?! Makes zero sense. I''m insulted

I'm very thorough, plus this isn't supposed to be an exciting deal. It's meant for boring insurance talk. The math itself won't be in the novel, just the actual answer. Don't be insulted, this is actually a topic that I've been wondering about for a while too, so it does give me an extra initiative to seek out this generalized answer. Writing the details of the crash is easy, having numbers behind it helps me to ensure that my scenario is plausible. 'Tis all :)

Each vehicle is constructed differently and will crush differently depending on where it's hit and by what. Where did you come up with numbers for the crush depth? Why aren't you asking if those numbers are plausible? How did you come up with specific weights for each vehicle? and what did the SUV hit? Where? All I'm saying is that for being a very thorough novelist there is an awful lot to be desired.

In a fiction novel you can pretty much write what you want and not be called out.. Unless your readers are very picky crash investigators excellent with physics.

make the car roll if you want. In real life it would either roll or not. it will be a better read if it rolls.

I'm not really insulted so much as incredulous, but I'll give you the benefit of doubt and think you must be quite the freak of a novelist with a peculiar interest in crash force.. So that can only be a good thing.

welcome to the forum btw

how about the pavement is it concrete, asphalt? is it wet or frozen? is the ground level? the amount of tread on the tires, air temperature, did the drivers apply brakes? at what millisecond? did the driver(s) turn the wheel to avoid colision? at what millisecond? where is the center of gravity in each vehicle? shape of the vehicle... to many variables to get a concise answer to your problem.

You forgot to factor in the difference between a duck, and not ducking.

If an object goes from a given speed to zero speed within a certain distance, its average acceleration can be computed. From there, F=ma can give the impact force. The relevant speeds involved will depend on angles of impact, not just the "straight" speeds of the individual vehicles.

In a novel, you wouldn't want to deal too closely with trig complications. That makes it challenging as to how to say enough without having to say too much.

This is awesome! That was the formula I had found, but I wasn't sure if it was the one I was looking for! Thank you so much for your help!

Whether the small car would roll over depends on its track width, the location of its center of gravity, and the coefficient of friction of the tires, and the height that the collision force is applied. If the couple of the collision force and the tire friction force is enough to lift the center of gravity vertically above the wheels, it would roll over.

It's hard to calculate how far it would roll.

You are AHH-MAZING!!! My scenario looks like it'll pan out after all! Another many many thanks to you!!

You are not writing for a new episode of "Bull" are you? What mitigating circumstances are present for the driver of vehicle #1?

"and the height that the collision force is applied."

And the "effective" coefficient of friction between the two colliding vehicles: it's easy to imagine a scenario where part of the large vehicle slides under part of the smaller and flips it over; on the other hand part of the larger vehicle may slide over part of the smaller and hold it down and result in the larger vehicle turning over, or, part of the larger vehicle might "dig in" to the smaller so that no slipping occurs.

To the OP: what about a picture? Don't forget to include (in the novel) lots of details about the analysis of the skid marks, that's how the forensic guys always work out what really happened in an accident.

No dash-cam, then?

There are loads of collision videos available for further study on . One might easily copy one of those into fiction.

For some reason, most of them happen in Russia.

Use momentum and impulse concept. You could model it in matlab or phyton in a very simplistic approach.

The roll-over thing is a sort of complicated task to simulate. This can be done with Finite Element Analysis, though there might be some open sources in the internet specialising impact and collisions of cars in 1D,2D or 3D perhaps. I don't know. Use google.

I drive a sports car, the CG is very low and a side impact would , more than likely, just slide the car opposite the impact. A tall mini van or smart car might roll over(higher CG). There are many factors which would have to calculated in.

<...sports car....> Those things tend to get pushed underneath other vehicles instead of impacting them.

Do any of the specific car makers have available test data on any of the individual types of collisions?...

As you have stated, it is imaginary and fictitious so anything may occur that you want write about. I think what you may be more interested in is, would the right person survive your idea.

Terminate it.

I'll be bock!

As your idea is fictitious, I don't see how your idea will be to what you may think. Your scenario will induce spin in the 1st vehicle in the opposite to travel. The vehicle impacting the 1st car will veer right, (assuming you are driving a vehicle on the left side of the road). Both vehicles would theoretically spin away from the impact in the opposite direction of travel.

The 3rd vehicle would have in effect a gap to ingress. So your calculation needs to be initial impact on 2 vehicles, one of which receives a 2nd impact in either direction of the spin, T boned on one side, there is more chance the vehicle will go upwards more than travelling a distance.

To obtain your scenario, logic says that the 3 vehicles would need to collide within split seconds of one another meeting on the junction. The creditability is then lost, as why would a driver turn out into two oncoming vehicles, so close to him?

Here's the full scenario I was thinking of:

Car #1 (2 passengers) is driving semi-close behind an ambulance because a loved one is being transported to the nearest hospital. Of course, when an ambulance is active, people have to steer to the side of the road and wait for it to pass. So here is when the crash occurs. The ambulance turns into the community hospital complex, Car #1 on its tail traveling at 35 mph. Car #2 (driver only) is coming toward them, unaware of Car #1, thinking it can out run the ambulance before it turns traveling at 44 mph. The ambulance completes the turn, but Car #2 collides just behind the front passenger seat of Car #1. This causes a slide, but immediately after the initial collision, Car #3 (SUV; 6 passengers) strikes the back of Car #2 at 57 mph.

Now, I was thinking that the force of the slide begins the momentum. Car #3's impact is initiated, pushing Car #1 to the curb, which would cause a single rollover, making Car #1 flip onto its hood.

Hopefully this gives much better context.

Car #1 is similar to the 2005 Toyota IST

Car #2 is similar to the 2008 Mercury Milan Premier

Car #3 is similar to the 2007 Suzuki XL7

IDK, I'm sorry, but I don't know what a Toyota IST is.

Second, a 2008 Mercury Milan Premier should be in the junk yard. It's 9 years old if it has normal miles, it would have 135K on it. I don't think it would be running at this point.

Third, a Suzuki XL7 isn't that much heavier than a Mercury Milan (500-600 lbs). Also, there are so few of these on the road, so having an accident occur with a Milan and XL7 is very unlikely.

I think a better choice would've been using the following cars for the wreck.

1. 2013-15 Toyota Corolla LE - there are tons and tons of these cars on the road.

2. Midsize car is a Toyota Camry LE - The number one selling car in the US for 15 straight years!

3. SUV - you need something bid. Hey, there are tons of those big 2001 to 2006 Chevy Tahoe's on the road now and they're heavy beasts.

And how does force of impact # make this credible or not? Nothing is predictable is any such scenario. If you tried to repeat the crash a dozen times you would have a dozen outcomes. Add that line to your book.

You were spot on for booring. Add a flaming bakery and I'll buy a copy.

Good luck in whatever this is actually about.

What author has inspired you the most?

I will gladly take that line.

I'm not sure the overall story would be your cup of tea lol, but thank you for your opinion :)

Forget having the baker run out aflame. Save the donuts!! I see them rolling out on fire - caramel fire that is!!!!

DOH!!!

I remember reading this very question in a chapter of an Algebra 1 student textbook.

In fact, every chapter in that book started off with a hypothetical fictional scenario.

I think you might get more attention if you include a scene similar to the unfortunate results of a certain rear-end collision that was amply described in the novel "The Hotel New Hampshire" by John Irving.