On Dec 30, 7:33*am, Keith Dysart wrote:
On Dec 30, 2:12*am, Roy Lewallen wrote:
What do you predict will happen?

I predict that the pulse arriving at the left end will
have the same voltage, current and energy profile as
the pulse launched at the right end and the pulse
arriving at the right end will be similar to the
one launched at the left.

They will appear exactly AS IF they had passed
through each other.

The difficulty with saying THE pulses passed
through each other arises with the energy. The
energy profile of the pulse arriving at the left
will look exactly like that of the one launched
from the right so it will seem that the energy
travelled all the way down the line for delivery
at the far end. And yet, from the experiment above,
when the pulses arriving from each end have the
same shape, no energy crosses the middle of the
line.

So it would seem that the energy that actually
crosses the middle during the collision is
exacly the amount of energy that is needed to
reconstruct the pulses on each side after the
collision.

If all the energy that is launched at one end
does not travel to the other end, then I am
not comfortable saying that THE pulse travelled
from one end to the other.

But I have no problem saying that the system
behaves AS IF the pulses travelled from one
end to the other.

On the other, it is completely intriguing that
a directional voltmeter could be placed anywhere
on the line and the voltage profile of the two
pulses can be recovered. And this is true even
at the middle of the line where, in the experiment
with identical pulse shapes, no current flows and
no energy crosses. But the shape of the two pulses
can still be recovered.

So in the end I say it is AS IF the voltage and
current pulses pass through each other, but the
energy does not necessarily do so. That way I
am not left with having to account for where the
reflected energy goes when it arrives back at
the source.

...Keith

While I wrote the above about the energy in the
pulse not flowing all the way across the line,
the same can be said for the charge. The charge
which describes the pulse does not all go across
the middle of the line; just enough charge
flows to reconstruct the pulse on the other
side.

So the similar question is: Is it the same pulse
if it is not the same charge? Or is it another
pulse that just happens to have the same shape?

...Keith