# Tale of two cars (Physics question)

**URL:** <https://boards.straightdope.com/t/tale-of-two-cars-physics-question/614543>\
**Category:** Factual Questions\
**Created:** [March 2, 2012, 1:50pm UTC](https://boards.straightdope.com/t/tale-of-two-cars-physics-question/614543 "2012-03-02T13:50:04Z")\
**Posts on this page:** 1\
**Page:** 9

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**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\
**Post date:** [March 15, 2012, 4:19pm UTC](https://boards.straightdope.com/t/tale-of-two-cars-physics-question/614543/161 "2012-03-15T16:19:01Z")

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> [@The\_Niply\_Elder](#):
>
> If the first test case was replaced with a red and green billiard balls, and the second case with a blue and yellow billiard ball, could you answer the question of “which one is more detrimental”? What would a postmortem forensic examination tell you? Nothing. There is nothing that you can conclude. Other than extreme simplifications of complex problems do not help you much.

Billiard balls tend to have elastic collisions, so neither is very “detrimental”. Unless you ramp the velocities up to 11, in which case the collisions stop being elastic. “Detriment” seems to require inelasticity.

It seems to me you’re overparsing the word “detrimental”. If you want to get into that level of detail, you’re going to have to specify which make and model of car, and what angle they intersect, the orientation and position of each car, whether one car is empty and the other is loaded with exercise weights, etc, ad nauseum. There was nothing in the OP to suggest he wanted a run down of how much each car collapsed, or if the trunk was sturdier than the hood, or if the windshield cracked or not, etc. He asked a very generic question with limited constraints, suggesting that he was looking for the textbook situation.

> [@Cheesesteak](#):
>
> The other issue is that the summarized version glosses over the fact that the Car vs. Car interactions are identical, and the differences occur in the Cars vs. Environment interaction that follows.

Exactly, thank you for coming up with this phrasing.

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