Question regarding cartridge outputs...

Could someone explain to me the difference between:
.6mV @ 1khz 5cm/sec
.6mV @ 1khz 3.54cm/sec

Thanks for your help.
The unit cm/sec refers to the groove velocity cut into a record. This is how manufacturers reference (quote) their RMS output voltage (the number is asually approximately 5.7cm/s RMS).

Why? Because the cartridge's output is proportional to its stylus' perpendicular velocity. Your figures state that the cartridge's output will be the same when tracking a record with a 1kHz waveform cut at either groove velocity.
I assume those numbers are for two different cartridges...

If that is the case the second cartridge will have significantly higher output when tracking a track with say a groove velocity of 5 cm/sec. In fact output will be around 0.85mV for that track for cartridge 2 vs. 0.6mV for cartridge 1.

Seasoned's explanation of the numbers is correct as well.
to summarize the above, the output spec, in mV, is usually in reference to either 5cm/sec or 3.54cm/sec. The reference spec is often not listed so it can be important to research which one the company uses, as the actual output can vary by quite a bit, potentially making or breaking usability in a given system. To clarify Seasoned's last sentence, no cartridge has the same output forboth velocities.
Curious. Then the output of a cartridge DECREASES as the needle follows the groove spiraling into the center??? As the outside velocity is at least twice the inner velocity?
(my thought was the different velocity measures given referred to the cart at the outside edge @ 33 1/3 rpm, vs the middle of the record.)
Is the loudness difference between the outside edge, vs near the inner end, hearable?
(I have never noticed it myself... but then I was never looking for it either!)
Restock, yes you are correct in assuming that these are two different cartridges. Piedpiper hit the nail on the head as for why I was asking. I use an all tube phono stage w/out any SUT's and have been contemplating getting a new cartridge. I've always noticed that some list the output referenced to 3.54 and others to 5cm/sec. I knew that it would relate to a difference in gain but wasn't sure as to which would sound louder. In my case, it could mean the difference of hearing tube rush if having to turn the volume controls up too high to compensate for the lower output.

I found it interesting that a .6mV rated at 3.54cm/second would have an output of .85mV in a track with a groove velocity of 5cm/second. Could you share the formula in order for me to calculate various output comparisons like that?

Thanks to all for their input and helping me understand this more fully.
I currently am using a Benz MO.9 which is said to be .9mV @ 3.54cm/second. If I were to switch to the Ruby3H which is said to be .7mV @ 3.54cm/ much difference in gain would I lose? Would it be very noticeable? Can it be expressed in db?

Thanks again.
Could you share the formula in order for me to calculate various output comparisons like that?

I just simply assumed a linear relation between the output and the velocity. That is 0.6mV at 3.54 translates to (0.6mV/3.54)*5 = 0.85mV.

I will make sure to check whether the linear assumption is good or whether my guess is wrong. In any case, cartridge 2 will play louder.
I guess that was correct:

From the Audio Glossary:
Velocity-Sensitive: If a phono cartridge is velocity-sensitive, its output is proportional to the recorded velocity at all frequencies. Magnetic phono cartridges are velocity-sensitive. A magnetic cartridge will produce a flat frequency response playing a constant-velocity recording characteristic. When playing a constant amplitude recording, its output increases as the frequency rises.
There is a 6dB difference with every doubling or halving of the cartridge voltage output. Thus an output of 1mV is 6dB louder than one of .5mV.

The relationship of the output referenced to 3.54cm/sec and 5cm/sec is simple. If you divide 5 by 3.54 you get approximately 1.4, Conversely if you divide 3.54 by 5 you get approximately .7. If you have an output of .7@3.54cm/sec and want to translate that to the slightly more common 5cm/sec reference you multiply .7 by 1.4 and get approximately 1mV@5cm/sec.

The relationship of the Ruby to the MO is about 1.2dB.
Thank you so much for the detailed answers and making this easier for me to understand. The knowledge that you all share with the people in this forum is a great asset and is much appreciated.