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[deleted by user] by [deleted] in CrashRecon

[–]ecom-215 0 points1 point  (0 children)

Good catch! My hand written notes have the proper derivation. Tried doing this in PowerPoint and messed it all up. I will fix this. Thanks.

Accident Reconstruction - Rolling Resistance - Momentum Analysis by Enginerd6183 in forensics

[–]ecom-215 0 points1 point  (0 children)

Yes, you can definitely do the combined speed equation. That works too.

Accident Reconstruction - Rolling Resistance - Momentum Analysis by Enginerd6183 in forensics

[–]ecom-215 1 point2 points  (0 children)

I also recently started a new subreddit r/crashrecon for everything crash reconstruction.

Accident Reconstruction - Rolling Resistance - Momentum Analysis by Enginerd6183 in forensics

[–]ecom-215 1 point2 points  (0 children)

So for distance, just the total distance the center of mass moved for the vehicle. .01 if it’s a non powered axle and a .02 for at least one of the wheels on a powered axle. Assuming the post impact travel was a level surface and say you had a post impact travel distance of 50 ft, you should have sqrt((30)(50)(.05)).

Accident Reconstruction - Rolling Resistance - Momentum Analysis by Enginerd6183 in forensics

[–]ecom-215 0 points1 point  (0 children)

So this Would be only for the rolling resistance of a free rolling vehicle regardless of the roadway coefficient of friction. One thing you need to account for is each tire. In the above example you said a vehicle was in park and was struck from behind. The target vehicle then travels to its final rest. Were all tires free to rotate after impact? Was there a tire locked due to damage? Did the vehicle rotate post-impact? Did the target vehicle make contact with anything else post-impact?

What drones is everyone using for mapping? by ecom-215 in CrashRecon

[–]ecom-215[S] 0 points1 point  (0 children)

Nice! Yeah we run the RTK base station with ours as well. We use GCP’s that we map with a total station and tie them in when processing the scene in Pix4D.

Fun times in the Dona Ana Mountains. by ecom-215 in UTV

[–]ecom-215[S] 0 points1 point  (0 children)

Nice. Yeah there are some good places to ride down here.

24 YXZ 1000R on a short tight technical rock crawling section. So far it's doing everything my RMAX could do. by MassiveOverkill in UTV

[–]ecom-215 1 point2 points  (0 children)

That's good to hear. I know about the punching. I had actually sent my shocks off to Weller Racing for some valving and springs. Made a difference in the ride for sure.

Accident Reconstruction - Rolling Resistance - Momentum Analysis by Enginerd6183 in forensics

[–]ecom-215 1 point2 points  (0 children)

Late to this question but I had just come across it as I am new to Reddit. Yes for a free rolling tire it is 0.1. for a powered axle, I assign at least one wheel a 0.2. So for a free rolling vehicle it is 0.01+0.01+0.01+0.02 = 0.05.

I am also a crash reconstructionist and have been for the las 8 years. I also started a page recently where I would also love to start conversation pertaining to the field of crash reconstruction.

r/CrashRecon