Re: vertical displacement from lorentz law



Somewhat clearer- so at max force the wire is perpendicular to the field and
the force is perpendicular to both (up or down, for your picture which
doesn't indicate field and current direction). Turn the picture 90 degrees
and what you have reduces to a common picture of a single conductor in a DC
machine. The rotation is different and similar to the conditions faced by an
end turn in a DC machine's rotor.

You already have an expression for the force. Now what is the problem?

You have not said how you maintain a current in the wire.

--

Don Kelly @shawcross.ca
remove the X to answer
----------------------------
"a@xxxxx" <a@xxxxxxxx> wrote in message
news:435382d3$0$1026$8fcfb975@xxxxxxxxxxxxxxxxxx
> ok, am working on a drawing
> meantime, I shall try and give you as best a "picture" as I can :
> two magnets a few cms apart (N ---- S) :
>
>
> ---------------
> / --------------------
> / | // /
> / | - - - - - - //- - - - - - - - /
> ------------ | - - - - - //- - -- - - - - - -----------------------
> | | - - - - -// - - - - - - - - - |
> | | - - - - // - - - - - - - - - |
> ----------- /
> ---------------------
>
> right, the wire (//) starts parallel to the field lines (- - - - - -) and
> hence no upward force
> (F=Bil sin theta=0 if theta=0, which is the angle between the field lines
> and the wire=> no force).
> As theta increases the wire turns into the plane of the screen, sin theta
> increases and thus so does the upward force.
> if this any clearer ? or do you need a drawing ? (not being rude here)
> thanks.
>
> G
> "Don Kelly" <dhky@xxxxxxx> wrote in message
> news:Jnj4f.210459$tl2.77158@xxxxxxxxxxx
>>A better description of the setup is needed. Presently it is difficult to
>>visualise what arrangement that you have in mind. Hence the presence of an
>>upward force cannot be assumed.
>>
>> --
>>
>> Don Kelly @shawcross.ca
>> remove the X to answer
>> ----------------------------
>> "z@xxxxx" <p@xxxxx> wrote in message
>> news:4350cabf$0$27411$8fcfb975@xxxxxxxxxxxxxxxxxx
>>> hi everyone,
>>> I wish to build an experimental device that is designed to show the
>>> upward displacement of a wire as it is rotated in a magnetic field
>>> produced by two magnets.
>>> as I understand it, the force that is going to produce this displacement
>>> is given by F=Bilsin theta, where B is the strength of the magnetic
>>> field, i is the current intensity through the wire and l the length of
>>> said wire. theta is the rotation if the wire, zero when parallel to the
>>> field lines.
>>> given values for B,i and l, how can I _calculate_, from F, the
>>> displacement of the wire in order to know the size of the device to
>>> build?
>>> I would have thought this could be obtained by introducing F=ma to give
>>> a=(Bilsin theta)/m, then integrating twice to get the position since
>>> this depends upon theta ? with dx/dtheta=x=0 when theta=0 as initial
>>> conditions ?
>>> am I going in the right direction here?
>>> any help appreciated, thanks.
>>> GT
>>>
>>
>>
>
>


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