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Rod McInnis
 
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Default Trailer Axel / Physics Puzzler


"basskisser" wrote in message
om...

The torsional forces can not have any effect on the trailer balace as

long
as the wheels are round or allowed to rotate.


Bull****. Are you telling me that if you have a moment arm, and apply
a torsional spring constant to it, that it won't try to rotate about
the axis of the axle????????


Nope. If the wheel is free to rotate (which it will be unless the brakes
are applied AND the wheel is somehow contrained from rotating) then there
will be no moment about the axel.

There will be a moment about the torsion bar, which is NOT the axle .

If that is true, then a torsion spring,
and it's ensuing torsional constant, aren't doing any work.


Correct! Any engineer would be able to tell you that the forces exerted by
a spring (including a torsion bar) do no work when they are at a steady
state condition. A spring will store "potential" energy. While it is
holding that engery it does no work. Work requires a force applied over a
distance. Just an applied force does no work.


Duh.....that's why I asked...geez... AND, how do you know WHERE that
center of MASS will be?


Well, geeze, he said very clearly that he put the boat on the trailer
(actually, he said he put the trailer under the boat) such that the boat was
sitting on the trailer as it was expected to be. Thus, any measurements he
takes will be for the boat + trailer. What each one individually is doesn't
matter for the purpose of this discussion.

So, now you want to talk about center of mass as opposed to center of
gravity?


Nope. On level ground and constant velocity it doesn't matter. To expand
the discussion to include an "accelerated frame of reference" is a lot more
work.

My point is, he didn't mention the relationship between the center of
mass of the boat, and the center of mass of the trailer.


Which is totally irrellavent. He only needs to be concerned about the two
together, which he has taken care of by putting the two together when he
made his measurments.

What is YOUR point? I notice you've not interjected one thing to help.


My point is that some of your comments are false and do nothing but confuse
the issue.

Rod