No ones thinking about momentum.


On 2/29/2012 7:38 PM, Brett Nordgren wrote:
> Bob & Geoff,
> 
> I'd missed that part of the original question, and Bob is quite right. 
> Gravity (an acceleration) and the ground motion you want to see (which
> may also be viewed as acceleration) can't be separated from each other. 
> When you manage to cancel out the first one, you also end up canceling
> out the second.  Unfortunately, no way around it.
> 
> Gravity is just a (huge) DC component of the same motion you want to
> measure.
> 
> Brett
> 
> At 01:55 PM 2/29/2012, Bob McClure wrote:
>> Hi Geoff,
>>
>> Making the mass of a seismometer neutrally buoyant will get you
>> nowhere. The mass will not differentially move with respect to the
>> frame when external acceleration is applied. You may be able to
>> demonstrate a long period, but you will get no signal.
>>
>> Bob
>>
>> On Wed, Feb 29, 2012 at 1:40 PM, gmvoeth
>> <gmvoeth@.........> wrote:
>> Hello Mr. Nordgren,
>>
>> You speak in a way I might be able to understand.
>>
>> What I was wondering is that buoyancy can be implemented in ways
>> which might produce spring like results possibly one might
>> use a "weak spring (low weight/inches)" with whatever mass
>> in combination with buoyancy "like a submarine or ship" to
>> produce extended or lower frequencies using shorter lengths.
>> simply submerging the mass within a dense liquid may allow
>> this to happen.
>>
>> has such a thing ever been tried ?
>>
>> I saw this research ship which could be flooded
>> to float like a fising bobber ? it made me think
>> of other things like this one above.
>>
>> thanks for your responses.
>>
>> regards,
>> geoff
> 
> 
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