friday the 13th, biker down

[dannymax]

I'm going to disagree with you on this one based on the fact that others have already commented on. The weight differences are so different that I was making the assumption that the truck, bumper, etc. did not deflect or move at the moment of impact and remained at the same speed. Of course this isn't true there would be some 'give' by the truck, there is also going to be the deflection of the front tire and forks that start to slow the bike down before the body hits the truck. A few miliseconds can make a HUGE difference in impacts. Look at air-bags, hitting a pillow of air for a fraction of a second makes a WORLD of difference.

Anyway, back to the change in acceleration debate. There would be a change of 130mph if we assume that the motorcycle has to not only slow from it's rate of speed, but also has to reverse directions (to what the speed of the truck was traveling at)... this is once again assuming that the truck's rate of speed does not chage.

:ummm:It's been a while, but I think I'm on the right path with this thinking... if we keep going with this I'm gonna have to invite some friends over and get some smoke out so I can really get into some deep thought!unk:

Jeff

This is all very true and even the slight resistance created by the collapsing forks would lessen the impact....not enough to make any difference to the biker but certainly mathematically.

The cancelling part is what I'm still not getting. :ummm: Granted, I'm not a mathematician or physicist or whatever but it seems to me that, given two vehicles of identical weight hitting head-on....there will be substantially more damage if both vehicles are travelling at 60 mph, as opposed to one vehicle being stopped.

If they were both going 60 mph, and hit head-on, and the forces cancelled each other out.....why wouldn't both drivers just step out, shake hands and go have a beer?

I must be missing something here! :confused2:

 

[mattness]

well the people inside the car would still be moving way too fast... airbags stop people... we're not talking about the bike/car slowing down... its the person on the bike he was still moving 60 mph... hell he coulda hit the brakes so hard he dead stopped but he wouldve flown over the bike at 60 mph lol

 

[hubeerjw]

http://warp.povusers.org/grrr/collisionmath.html

This is about the easiest explanation I have found.

 

[mattness]

so theyre playing a trick on us like the airplane on a conveyer belt taking longer to take off.. however it states this

"Vehicle 1 applies the equivalent of 50 km/h times its mass to vehicle 2, and vehicle 2 applies an equal force to vehicle 1. This causes both vehicles to stop right there. "

thats not the case. they arent equal vehicles hitting each other. its a 10 ton truck vs a 500 lb bike

 

[mattness]

and again

"Update: In a recent episode of Mythbusters they tested this conundrum in practice because fans complained about Hyneman's comment, and it showed the theory to be completely right: Two identical cars hitting each other head-on at 50mph is equivalent to one of the cars hitting a wall at 50mph (and nowhere even close to hitting the wall at 100mph)."

 

[mattness]

it would be like clapping your hands together or on the table is what hes explaining.

but when you compare a fly getting smacked by your hand.. the fly got it bad

if the mass was equal the fly would have stopped your hand

or like 2 180 pound basketball players jumping at each other in the air and givin g each other a high five and both fall straight back down...

 

[mattness]

but still id rather hit a brick wall than a head on collision LOL

 

[dannymax]

http://warp.povusers.org/grrr/collisionmath.html

This is about the easiest explanation I have found.

Thanks Jeff....I got it!! Being a visual type it took the weights & pulleys image to finally drive it home but it makes sense now! :worthy: