Determine speed of car from result of impact?

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Discussion Overview

The discussion revolves around the possibility of calculating the speed of a car involved in a collision based on available data, including the displacement of the parked car, the masses of both vehicles, and the friction of the road surface. The context is exploratory, focusing on accident reconstruction and the physics involved in determining velocity from impact data.

Discussion Character

  • Exploratory, Debate/contested

Main Points Raised

  • One participant expresses curiosity about calculating the velocity of their car after being hit while parked, providing details about the displacement and vehicle masses.
  • Another participant asserts that accident reconstruction is complex and that any idealized calculations would likely not be accurate.
  • A different participant suggests that while making assumptions could yield a rough estimate, they suspect the other vehicle was traveling faster than 25 mph based on airbag deployment.
  • One participant reiterates that assistance with accident analysis and reconstruction is not provided in the forum and recommends consulting a specialist.

Areas of Agreement / Disagreement

Participants generally agree on the complexity of accurately calculating the speed from the given data, with some expressing a willingness to make assumptions for a rough estimate, while others emphasize the limitations of such an approach. The discussion remains unresolved regarding the feasibility of obtaining a precise velocity calculation.

Contextual Notes

Limitations include the assumptions required for any calculations, the potential inaccuracies in idealized models, and the lack of specific details about the collision dynamics.

doggonemess
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Greetings,

It's been quite a while since I had to do anything with velocity, friction, mass, and practically any physics over simple calculations. My car was hit yesterday while parked. There were no injuries, and it still drives just fine. The collision was hard enough to deploy the other car's airbag.

I don't need to know the answer for legal reasons, it's all being taken care of by insurance. But out of curiosity, is there a way to calculate the velocity of the car from the data that I have?

I can tell from how offset my car is from straight how much it moved. I know the masses of both vehicles, as well as the road surface where my car was sitting for the friction of the tires.

Can someone noodle this one out? I'd love to know.

Jamie
 
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doggonemess said:
is there a way to calculate the velocity of the car from the data that I have?
No. Accident reconstruction is a very tricky business. Of course you can do some idealised setup where you can input what you know, but it will not be very accurate.
 
Orodruin said:
No. Accident reconstruction is a very tricky business. Of course you can do some idealised setup where you can input what you know, but it will not be very accurate.

I'm happy with making some assumptions and getting a ballpark figure. I suspect they were going faster than 25 mph due to the airbag deployment. I'm wondering if they were going much faster than that.
 
doggonemess said:
Greetings,

It's been quite a while since I had to do anything with velocity, friction, mass, and practically any physics over simple calculations. My car was hit yesterday while parked. There were no injuries, and it still drives just fine. The collision was hard enough to deploy the other car's airbag.

I don't need to know the answer for legal reasons, it's all being taken care of by insurance. But out of curiosity, is there a way to calculate the velocity of the car from the data that I have?

I can tell from how offset my car is from straight how much it moved. I know the masses of both vehicles, as well as the road surface where my car was sitting for the friction of the tires.

Can someone noodle this one out? I'd love to know.

Jamie
As already pointed out, we do not help with accident analysis and reconstruction here. Please consider hiring a specialist to help you with this.
 

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