Fatality on Devil's Whip (NC)

[Journeyman]

Update on the accident. According to police the bike was traveling over 100 mph in the turn when he crossed the center line with his girlfriend on back.

Troopers: Motorcyclist in fatal Marion wreck was doing ~100 mph, went left of center

 

[Dr.D]

Doc, with due respect, you wife is as good a rider as you are.

You got a good point there. The lady sure can ride a big bike.

 

[1olbull]

Update on the accident. According to police the bike was traveling over 100 mph in the turn when he crossed the center line with his girlfriend on back.
Troopers: Motorcyclist in fatal Marion wreck was doing ~100 mph, went left of center

FYI - Food For Thought:
Curious how they arrived at a speed of 100 mph for the MC?
Google will not show the road in street view, but let's assume the speed limit on Old Clear Creek Road is 50 mph.

The 2001 Toyota Sienna Van has a gross weight of 4,000 pounds, without counting for passengers and cargo weight.
The MC is likely 800 pounds plus two passengers for maybe another 400 pounds = 1200 lbs total.

Newton's 3rd law is Balanced Forces, it says:
The external force acting on one vehicle is equal and in the opposite direction to the force acting on the other vehicle (2 vehicle collision) or object (solo vehicle collision).
Therefor, in a head-on, the Force of veh1 equals the Force of veh2.

Force = mass x acceleration (Newton's 2nd law), therefor, the MC weight times its speed = the Van weight x its speed.
Van 4000 lbs X 50 mph = MC 1200 X 100 mph
200,000 = 120,000 Not equal is it???
If the Van was traveling at 50 mph, the MC had to be traveling at 167 mph!

Set up the equation:
Van 4000 lbs X 50 mph = MC 1200 X Speed in mph
200,000 = MC 1200 X Speed in mph
200,000/1200 = MC Speed in mph
MC Speed in mph = 166.67 mph

Now if the speed limit and speed of the Van was just 30 mph things work out better:
Van 4000 lbs X 30 mph = MC 1200 X 100 mph
120,000 = 120,000

 

[Steel]

You got a good point there. The lady sure can ride a big bike.

And looks way better than you while doing it.

 

[TURBO200R4]

Herman,
I sure hope that was not me?!?!?

since when have u ever been in the middle
i was not talking about the raa riders they were all expert.
was talking about one of my trips to "TOO BROKE FOR STURGES" just south of Flagstaff.

 

[Jerry C]

Force = mass x acceleration (Newton's 2nd law), therefor, the MC weight times its speed = the Van weight x its speed.
Van 4000 lbs X 50 mph = MC 1200 X 100 mph

Force = mass X acceleration is a correct formula. 50mph and 100mph are speeds (velocity if direction is included). This is not a legitimate substitution and probably will not produce accurate answers. It may work IF both vehicles stopped right at the collision point. More than likely the motorcycle's velocity changed from something forward to something backward. In that case, its change in speed more than 100mph.

Later,
Jerry

 

[TURBO200R4]

my expert calculations
if u are riding at 100 mph and there is something solid in front of u.
u have about 2 seconds to kiss your a$$ good by

 

[sonny]

my expert calculations
if u are riding at 100 mph and there is something solid in front of u.
u have about 2 seconds to kiss your a$$ good by

We both think along the same lines.

 

[1olbull]

since when have u ever been in the middle
i was not talking about the raa riders they were all expert.
was talking about one of my trips to "TOO BROKE FOR STURGES" just south of Flagstaff.

Whew!!!
I was worried there for a moment . . .

 

[1olbull]

Force = mass X acceleration is a correct formula. 50mph and 100mph are speeds (velocity if direction is included). This is not a legitimate substitution and probably will not produce accurate answers. It may work IF both vehicles stopped right at the collision point. More than likely the motorcycle's velocity changed from something forward to something backward. In that case, its change in speed more than 100mph.

Later,
Jerry

Not so, Amigo!
Tis a balanced Force ratio, ONLY (no vectors necessary).
Weight times speed can easily substitute for mass times velocity, whatever the units as long as they are consistent.
FYI - "MPH-foot pounds" is a legitimate quantity used in collision reconstruction world wide.

We are not quantifying speeds based upon scene data or attempting a linear momentum equation solution, therefor, post impact travel and rest is also unnecessary.
Also be aware that no scene data was provided and we do not know which vehicle had the greatest momentum or as you stated, "More than likely the motorcycle's velocity changed from something forward to something backward." Therefor, if the motor was in fact traveling at 100 mph it could indeed have pushed the Van backward if it had been traveling under 30 mph.

Third Law: Balanced Forces
The external force acting on one vehicle is equal and in the opposite direction to the force acting on the other vehicle (2 vehicle collision) or object (solo vehicle collision).
Another description: To every force there is an equal and opposite reaction, or the mutual actions of two bodies are equal and opposite.