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Delta V question

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First Name: Mike
Last Name: Phillips

Delta V question

Post by MikePhillips4 » Fri Nov 10, 2017 1:41 pm

Scenario: Vehicle A, ’04 Pontiac G6, made a left turn, southbound to eastbound, from a stop and had accelerated to 12mph according to the EDR pre-crash data. Vehicle B, ’04 Toyota Solara, was northbound and collided front to the right front quarter/right passenger of vehicle A. The intersection is controlled by a traffic signal and it was green for north and southbound traffic at the time of the crash. Vehicle A’s EDR reported a delta V of 12mph. The data doesn’t specify lat. Vs long. for the delta V so I believe it to be solely long. since its forward motion was stopped. Vehicle B’s EDR reported no pre-crash data and delta V of 43.5. The curb weight of vehicle A is about 200 lbs heavier than vehicle B. The collision was 90 degrees. Post impact speed for vehicle A was calculated to be 49 mph. Vehicle B was calculated to be 31 mph but did not included speed loss due to striking a pole. FWIW witness stated vehicle B was racing another vehicle, the speed limit was 35mph. I have two primary questions:
1. Is it possible for vehicle A to have a post impact speed(49mph) greater than vehicle B’s delta V (43.5) given that A is heavier than B?
2. Can vehicle B’s delta V and its post impact speed be added or does it have to be combined?


Thank you for your time.
“In theory, there is no difference between practice and theory. In practice, there is.” Unknown

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Re: Delta V question

Post by mchenrysoftware » Mon Nov 27, 2017 11:02 am

you say 'post impact speed was calculated' check your assumptions since drag factor? amount of rotation? terrain up or down?
and on question of adding deltaV and post impact speed...see Beginners Error#1 in Reconstruction 101 includes a similar type question of how to combine speeds


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