dickhead jailed - GOOD!!

Post by **Vtecmec** » Tue Nov 18, 2014 6:39 pm

wurlycorner wrote:Both doing 40mph = 80 mph differential/impact speed.

Err, are you sure about that?

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Nov 18, 2014 6:56 pm

Errr, yep?
40mph+40mph = 80mph

'92 Si VTEC · Post by **jjmartin349571** » Tue Nov 18, 2014 7:04 pm

Equal and opposite forces means it's like a 40mph impact, the speeds don't sum up.

'92 Si VTEC · Post by **jjmartin349571** » Tue Nov 18, 2014 7:06 pm

Also, back on topic - I know of someone who got a driving ban, then was caught two further times driving dangerously with no licence or insurance. He got a slap on the wrist first time round and a suspended sentence second time round. He's caused a couple of accidents too and I think it's a body lemonade take he gets off so lightly compared to the kiddy who drove out on a race track. It's much more of a danger to be driving badly on public roads imo.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Nov 18, 2014 7:15 pm

Ok, it's not linear in the effect of the crash (mass of each of the vehicles comes into it etc) so the effect of the crash isn't necessarily like an 80mph crash, but it's not equivalent to a 40mph crash with a stationary object either and I was talking about closing speed...
The point I was making was that on the racetrack the cars were going in the same direction, so even if the polo was going slower than the others, if one ran into another the differential between the 2 vehicles is far less than the differential between the polo and another car coming in an opposing direction on a public road (even if both vehicles were each travelling at a slower speed on the public road).

mercutio · Post by **mercutio** » Tue Nov 18, 2014 9:04 pm

jjmartin349571 wrote:Equal and opposite forces means it's like a 40mph impact, the speeds don't sum up.

think people get mixed up with closing speed

Post by **Donald** » Tue Nov 18, 2014 11:10 pm

wurlycorner wrote:Ok, it's not linear in the effect of the crash (mass of each of the vehicles comes into it etc) so the effect of the crash isn't necessarily like an 80mph crash, but it's not equivalent to a 40mph crash with a stationary object either and I was talking about closing speed...
The point I was making was that on the racetrack the cars were going in the same direction, so even if the polo was going slower than the others, if one ran into another the differential between the 2 vehicles is far less than the differential between the polo and another car coming in an opposing direction on a public road (even if both vehicles were each travelling at a slower speed on the public road).

I see what you mean now!

In a sliglthy addled state its something like mv^2 of vehicle 1 plus mv^2 of vehicle two divided by the sum of something squared. But this is not accounting for elasticity.

An inelastic collision you can use equation to figure out the force on one car at the moment of impact

F=(-0.5mv^2)/distance taken for vehicle to stop

mercutio · Post by **mercutio** » Wed Nov 19, 2014 8:42 pm

yeah that's me bored now