From: "JACK L. URETSKY (C)1998; HEP DIVISION, ARGONNE NATIONAL LAB ARGONNE, IL 60439" <JLU@HEP.ANL.GOV>
Date: Thu, 1 Jul 1999 22:52:00 -0500
Hi Jaes Wheeler-
You write:-
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Once a teacher in my high school asked a similar question:
Which is worse-a head on collision with an identical car travelling the
opposite direction with equal speed, or a collision at the same speed with
an immovable brick wall.
( I wonder how he graded the responses?)
The doubling of the speed before hitting the immovable object has several
nasty effects. The car will need to get rid of four times the kinetic
energy, and may experience twice the force.
(if the collision times are equal)
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Isn't there an unstated assumption here? Does the worsity (how bad)
of the collision depend upon the reference frame in which it is observed?
Regards,
Jack
"I scored the next great triumph for science myself,
to wit, how the milk gets into the cow. Both of us
had marveled over that mystery a long time. We had
followed the cows around for years - that is, in the
daytime - but had never caught them drinking fluid of
that color."
Mark Twain, Extract from Eve's
Autobiography