# Stationary Forces in a Car Collision

1. Apr 25, 2013

### freelancer799

I'm trying to find out the force on a collision that happened to me recently, nothing serious but the lady went away in the ambulance for what I believe wasn't that much force exerted on her at all.

Both vehicles were at a stationary position about 2.5 meters away from each other. The second vehicle (mine) having a curb weight of 1200 kg travels to a peak velocity of about 2.23 m/s and strikes the first car on the bottom part of the bumper on the left side when that vehicle weighs in at about 2600 kg.

Now I understand that the car probably took most of the force but I want to figure out what the max force was and compare it to a real world example for insurance to investigate. I figured I would use an impact force formula like:

F= m*(vf-vi)/(tf-ti)

But wasn't sure if that was the proper approach. With that I was able to get about 1300 N of force

Forgot to mention it took about 2 seconds for me to hit her, maybe not even

Last edited: Apr 25, 2013
2. Apr 25, 2013

### Staff: Mentor

It is impossible to calculate the force without an analysis of the length (or timescale) of the acceleration of the woman in the car.

As an example: You can fall down 1m, and won't experience significant forces if you use your legs to decelerate within ~50cm. If you drop a pen, on the other hand, it will stop within <1mm, and experience accelerations of the order of 1000g (1000 times the gravitational acceleration of earth).

3. Apr 25, 2013

### nitsuj

Newer air bag trigger systems are essentially accelerometers.

That said, perhaps the doctor and the patient will know better than the formula.

It is not at all unreasonable for someone with a preexisting neck / back injury to be driving a vehicle, the only "stipulation" I can think of is that you can operate the vehicle properly...from a physical perspective of course

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