-J-P-L-

Many familiar with physics will probably know the result. This is a long time belief based on intuition.

What do you think?

Part 1 http://www.youtube.com/watch?v=q_vCuE4KaUU

Part 2 http://www.youtube.com/watch?v=c-JGIYLZZUg

^ two parts at almost 11 minutes each but you really only need to watch the second one as the first one is preliminary testing. Worth the 11 minutes!!

The result actually proved Jammie wrong!

YotaCarFan

I would think that it's equivalent to hitting a wall at 50 mph. When two identical cars going 50 hit each other, they will both "stop" since each has the same momentum (mass times velocity). The same happens when the car hits the solid wall.

bruce van

Great post. That was fun watching.

RA40

iTrader: (6)

Good viewing...thanks!

"I love smashing stuff for science."

mxis350

WOOOOW that 100 mph crash was just unexpected.... You guys think a High safety rated car would do the same??

darkdream

The g forces alone would most likely kill the occupants at 100 mph.

syzygy

Two cars of mass M crashing into each other at 50 MPH each is equivalent to one car of mass 2M crashing into a stationary wall at 100 MPH.

Mv350

iTrader: (23)

that was sweet!

GSteg

iTrader: (15)

You didn't see the video? 2 cars travelling at each other at 50mph were practically equivalent to one car hitting the wall at 50mph. It wasn't even close to one car (1M) hitting the wall at 100mph.

STIG

I think 2 cars hitting head on at 100mph would be different from one car hitting the wall at 100mph.

GiantsFan

iTrader: (9)

I watched it when it aired, good episode

Pearlpower

iTrader: (2)

makes sense and a great episode

GSteg

iTrader: (15)

Of course because we're dealing with inelasticity. But 2 cars going at each other 50mph is wayyy different than one car with twice the mass hitting a wall at twice the speed.

syzygy

The video confirms precisely what I said in my previous post (it's mentioned at the very end of the second youtube click where they show the math).

2 cars each of mass 1M hitting each other at 50 MPH is, indeed, equivalent to 1 car of mass 2M hitting a wall at 100 MPH.

That's the trick here, it's simple conservation of energy. You have a certain amount of kinetic energy being transferred as wreckage into both cars (total mass 2M) when 2 cars of mass 1 M hit each other at 50 MPH.

From a conservation of energy perspective, this is equivalent to 1 car of mass 2M hitting a stationary wall at 100 MPH.

It is not equivalent to 1 car of mass 1M hitting a 100 MPH wall, as was indicated by the video.

syzygy

2 cars of mass M hitting each other at 50 MPH is, indeed, not the same as 1 car of mass M hitting a stationary wall at 50 MPH. That's the simple part.

(1/2)(m)(v)^2 + (1/2)(m)(v)^2 = total energy
mv^2 = (1/2)(M)(2v)^2

where m = mass of car 1 and car 2
M = equivalent mass of a single car necessary to simulate the same collision for a one car-one wall set up

2mv^2 = 4Mv^2

M = 2m


Edit: That's totally wrong. That's yielding a result of M = (1/2)m

Interesting. I think this result is implying that 2 cars of mass m hitting each other at velocity v is equivalent to 1 car of mass (1/2)m (not 2m like I stated previously) hitting a single stationary wall at velocity 2v

Someone help out and clarify the math please.