> True, but in Earnhardts accident, the enery was dissipated instantly.
> That was sort of my point. No amount of breakaway parts or a carbon
> fiber tub is going to prevent a 180 to 0 MPH impact against concrete.
> Tim
That's exactly the point. If you build a car as strong as a tank, it
will not deform on impact but simply stop almost instantly upon
collision with the wall. Simple physics (average force times the time
interval equals mass times the change in velocity) will tell you that if
a car disippates a given momentum (mass times the change velocity) upon
collision, the average force acting on the car and therefore average
acceleration (average force divided by mass of the car) on the driver
within it is inveresly proportional to the time that the deformation
takes place.
So, if a car is build very rigid, the time spent in a collision is much
shorter than it would be if a car is deigned to crumple as much as
possible (without deforming the driver cell, of course), and the short
times involved create large accelerations and it is these that cause
injuries.
-Gregor