On Oct 9, 11:00 pm, tommytoyz wrote:
Bob,
You have to remember that your vehicle was badly damaged BECAUSE it
weighs so much. The frame of your vehicle had to absorb your weight. A
lighter vehicle would not have to absorb as much energy to come to s
stop, as it weighs less.

And absorbing energy the principal reason why, in a crash, it is
better to be in a steel vehicle than aluminium, and GRP or composites
are worst of all. After all, we sit on energy absorbing cushions for a
very good reason.

It doesn't matter if the vehicle hits an immovable object or if you
get hit by a moving object from the front. The calculation is the same
for your vehicle to come to s stop or decelerate. The mass your
vehicle plays a very important role and the heavier it is the more
energy needs to be absorbed and the more damage there will be.

While true, that's only half the story. If you remember you schoolboy/
girl physics, you will realise that in a collision kinetic energy is
*not* conserved whereas momentum *is* conserved. (The "missing" energy
appears as heat and sound

So what?

Well, if you think through what happens in a collision between
vehicles with different mass, and use conservation of momentum, then
the lighter vehicle will experience a greater delta-v than a heavier
vehicle. And consequently the lighter vehicle will also experience a
larger acceleration than the heavier vehicle. That's rather important
to the occupants, since it is principally the acceleration that
determines how much brain damage they sustain.


So to compare the damage to your truck and say that this would happen
to a lighter vehicle is just plain wrong. A lighter vehicle would
sustain less damage is constructed the same as the truck.

Yes, but what about the occupants?

The fact of the matter is though, that lighter newer vehicles can
absorb more energy per pound than heavier vehicles and thus would
sustain far less damage than a heavier vehicle.

Why is that? I've no reason to doubt you, but why?

I've seen a crash test of a smaller Renault against a Land Rover and
the Land Rover was in worse shape after the head on collision test -
especially the occupants.

So safety design and weight are the biggest factors in survivability.
All things being equal, it's safer to be in a lighter vehicle in a
crash as there is less energy for the frame to absorb.

That's the first time I have seen that statement.

The Ford F-150 is one example. And can your truck's roof even hold the
weight of the truck should it over turn? Light vehicles don't have
this problem and have a lower CG as well.

Probably true, and important in some cases.

Your breaking power is also less than a lighter vehicle's - contrary
to what many may think, again because of the heavier weights. Stopping
distances are less in a lighter vehicle - always.

If the lighter tow vehicle has good breaks,

Highly ambiguous in this context I think you mean "brakes"!

like most modern smaller
cars do and good tires, that are not that much smaller than your truck
tires, say 15-17 inches , then a lighter car will stop much shorter
than your truck.

Maybe true, but the car's stopping distance isn't the only
consideration.