| Topic: |
Science > Physics |
| User: |
"jclause" |
| Date: |
16 Sep 2005 01:39:37 PM |
| Object: |
velocity |
A question please, likely elementary to you fellows.
A loudspeaker voice coil (armature) moves forward from zero
velocity at 0.019262 meters per second. The rearward motion
of the magnetic pole and plates (which were also at zero velocity
from the start) in response to this is 0.00061 m/s. Then with
respect to the panel the speaker is mounted onto (assuming it
remains stationary and/or is the reference), is the velocity
0.019262 + 0.00061 = 0.019872 m/s.
In other words, had the magnetic pole and plates remained
stationary would the velocity be 0.019872 m/s?
Thanks for your consideration.
JC
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| User: "Steven Gray" |
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| Title: Re: velocity |
16 Sep 2005 06:18:33 PM |
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(jclause) wrote in news:11im4b9djj1ecfd@news.supernews.com:
A question please, likely elementary to you fellows.
A loudspeaker voice coil (armature) moves forward from zero
velocity at 0.019262 meters per second. The rearward motion
of the magnetic pole and plates (which were also at zero velocity
from the start) in response to this is 0.00061 m/s. Then with
respect to the panel the speaker is mounted onto (assuming it
remains stationary and/or is the reference), is the velocity
0.019262 + 0.00061 = 0.019872 m/s.
In other words, had the magnetic pole and plates remained
stationary would the velocity be 0.019872 m/s?
No. Basically, in the first case you're considering a situation in which
an impulse transfers energy to the speaker frame and the coil. In the
second case, the same energy is transferred to the speaker frame and a
heavy mounting, and to the coil. With the mounted frame so heavy that it
doesn't move, essentially all the energy goes into the coil in the second
case. But energy is proportional to the square of speed, so the speed of
the coil in the second case is less than the sum of the speeds in the first
case.
--
Steve Gray
sgray2@cfl.rr.com
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| User: "jclause" |
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| Title: Re: velocity |
19 Sep 2005 12:04:06 PM |
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In article <Xns96D3C49CA1D45sgray2cflrrcom@65.32.5.122>,
sgray2@NOcfl.rr.comSPAM says...
jc@the.web (jclause) wrote in news:11im4b9djj1ecfd@news.supernews.com:
A question please, likely elementary to you fellows.
A loudspeaker voice coil (armature) moves forward from zero
velocity at 0.019262 meters per second. The rearward motion
of the magnetic pole and plates (which were also at zero velocity
from the start) in response to this is 0.00061 m/s. Then with
respect to the panel the speaker is mounted onto (assuming it
remains stationary and/or is the reference), is the velocity
0.019262 + 0.00061 = 0.019872 m/s.
In other words, had the magnetic pole and plates remained
stationary would the velocity be 0.019872 m/s?
No. Basically, in the first case you're considering a situation in which
an impulse transfers energy to the speaker frame and the coil. In the
second case, the same energy is transferred to the speaker frame and a
heavy mounting, and to the coil. With the mounted frame so heavy that it
doesn't move, essentially all the energy goes into the coil in the second
case. But energy is proportional to the square of speed, so the speed of
the coil in the second case is less than the sum of the speeds in the first
case.
--
Steve Gray
sgray2@cfl.rr.com
Thank you.
JC
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| User: "PD" |
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| Title: Re: velocity |
16 Sep 2005 02:44:30 PM |
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jclause wrote:
A question please, likely elementary to you fellows.
A loudspeaker voice coil (armature) moves forward from zero
velocity at 0.019262 meters per second. The rearward motion
of the magnetic pole and plates (which were also at zero velocity
from the start) in response to this is 0.00061 m/s. Then with
respect to the panel the speaker is mounted onto (assuming it
remains stationary and/or is the reference), is the velocity
0.019262 + 0.00061 = 0.019872 m/s.
The velocity of the coil with respect to the panel is 0.019262 m/s.
The velocity of the pole with respect to the panel is -0.00061 m/s.
The velocity of the coil with respect to the pole is 0.019872 m/s.
In other words, had the magnetic pole and plates remained
stationary would the velocity be 0.019872 m/s?
Possibly, but this would likely violate momentum conservation. What
would happen instead is that the whole speaker would recoil at some
smaller velocity backwards, and the velocity of the coil with respect
to the panel would be somewhere between 0.019262 and 0.019872 m/s.
Thanks for your consideration.
JC
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| User: "jclause" |
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| Title: Re: velocity |
19 Sep 2005 12:01:42 PM |
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In article <1126899870.661271.56790@g44g2000cwa.googlegroups.com>,
TheDraperFamily@gmail.com says...
jclause wrote:
A question please, likely elementary to you fellows.
A loudspeaker voice coil (armature) moves forward from zero
velocity at 0.019262 meters per second. The rearward motion
of the magnetic pole and plates (which were also at zero velocity
from the start) in response to this is 0.00061 m/s. Then with
respect to the panel the speaker is mounted onto (assuming it
remains stationary and/or is the reference), is the velocity
0.019262 + 0.00061 = 0.019872 m/s.
The velocity of the coil with respect to the panel is 0.019262 m/s.
The velocity of the pole with respect to the panel is -0.00061 m/s.
The velocity of the coil with respect to the pole is 0.019872 m/s.
In other words, had the magnetic pole and plates remained
stationary would the velocity be 0.019872 m/s?
Possibly, but this would likely violate momentum conservation. What
would happen instead is that the whole speaker would recoil at some
smaller velocity backwards, and the velocity of the coil with respect
to the panel would be somewhere between 0.019262 and 0.019872 m/s.
Thank you.
JC
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