# Force / Car Collision

Joined Jan 12, 2021
40
Hi Folks! Hope all is well.

So I was reading this news article about a drunk driver ( Bad guy ) who somehow managed to drive in the opposite direction on a highway and crashed into another vehicle head on. The driver of the other car ( Good buy ) died. The bad guy was apparently going about 90 mph when the crash occurred.

Then it dawned on me...
What if the good guy himself, seeing that the crash was inevitable, accelerated his own car to 130 mph and hit the bad guy head on. Would the bad guy's car end up getting the higher amount of the crash force? Would the good guy have a better chance of surviving because the resultant force vector would have dumped all the energy into the bad guy's car? Does the good guy crashing into the bad guy's car help the good guy at all, according to Physics/ Force/ Vectors?

#### Delta Prime

Joined Nov 15, 2019
1,164
Hello there welcome to AAC
Here I pulled this out of blue sky for you F=(m) (a) Force equals mass times acceleration it would have been an accumulative effect. They would have both felt the same thing. Independent of who's going faster the construction of the vehicles would have been the deciding factor and who lives and who dies and just dumb luck. That's only one opinion there is going to be many more standby please.

#### wayneh

Joined Sep 9, 2010
17,153
No. The damaging entity in a crash is the combined kinetic energy. It has to all go somewhere and there's no reason the faster object would necessarily avoid its share. Deceleration before an impact is the best way to hugely knock down the energy involved.

Momentum also matters, though, so having a dramatic imbalance in momentum means the lower momentum vehicle is going to suffer a larger acceleration and g-forces. I don't think a couple seconds of intentional acceleration would significantly change the momentum comparison. Not enough to compensate for the danger of the added energy.

#### Papabravo

Joined Feb 24, 2006
17,028
Hi Folks! Hope all is well.

So I was reading this news article about a drunk driver ( Bad guy ) who somehow managed to drive in the opposite direction on a highway and crashed into another vehicle head on. The driver of the other car ( Good buy ) died. The bad guy was apparently going about 90 mph when the crash occurred.

Then it dawned on me...
What if the good guy himself, seeing that the crash was inevitable, accelerated his own car to 130 mph and hit the bad guy head on. Would the bad guy's car end up getting the higher amount of the crash force? Would the good guy have a better chance of surviving because the resultant force vector would have dumped all the energy into the bad guy's car? Does the good guy crashing into the bad guy's car help the good guy at all, according to Physics/ Force/ Vectors?

No speeding up would make the problem worse. You can compute the kinetic energy of a moving vehicle via:
$KE\;=\;\frac{1}{2}mv^2$
doubling your velocity will quadruple the energy. In a head on collision the energy is dissipated by both vehicles. However the more massive vehicle will be the last one to stop.

#### GetDeviceInfo

Joined Jun 7, 2009
1,897
imagine being thrown against a brick wall, at some speed, then ask if the speed at which you were thrown could impact the outcome. A vehicle would be worse though, as the force would be focused through the steering column. Yes, a well engineered vehicle can provide a mass deceleration on impact, but generally, the lower the speed of impact, the less trauma. Vehicle mass is less important than the occupants mass. We are not concerned as to the vehicles ability to survive impact, as we are the occupants.

#### Deleted member 115935

Joined Dec 31, 1969
0
Interesting thought,
if both cars had the same mass, and were going the same speed,
both would stop at the impact point, and the impact on both would be shared.

If one car was going double the speed,
then if the resultant kept moving, then the change in velocity of the slower car would be twice that of the faster car
i.e he faster goes from say 100 to 50, the slower one goes from 50 to - 50 .

But in reality , they are both going to stop,
I would suggest that the faster car has a deceleration in a straight line, whilst the slow car has a 180 degree flip in velocity,

this with air bags and seat restraint, the constant deceleration is probably better for the fast occupant than the occupant who initially is thrown forward and then the pressure comes off in the slow car.

Would be better, if they had sufficient time to accelerate, if instead they both hammered brakes on me thinks.