Tonearm/cartridge weight considerations


I have just decided to dig up my old vinyl collection that has been waiting for better days since mid-80s. Bought a turntable (Thorens 124) without tonearm. I have Shure V15V-MR cartridge. Started to look around for an appropriate tonearm and found out that the tonearm/cartridge issue has grown into a science. Now I am confused about this tonearm/cartridge weight issue. Could enyone illuminate me about this issue, mainly covering the following questions:
1) they speak of light/medium/heavy arms, so what are the figures for those weight categories?
2) are there weight categories for for cartridges and if yes - where my SHure V15V-MR fits?
3) does a light tonearm needs a light cartridge, or is it totally opposite - a light tonearm needs a heavier cartridge and vice-versa?
4) what can go wrong if the rules of tonearm/cartridge weight are ignored?
Thank you!
crockusbird
Welcome to A'gon! Someone may pop up with some direct answers, but you can probably find them by doing a search. You want to look for references to effective mass, compliance, and tonearm resonance. These topics have been covered extensively here.

Best,

Dan
Thank you for reply. I did some Audiogon archive search, however here in Audiogon most of the relevant topics are about specific arms and specific cartridges whereas my question was more general, perhaps even more theoretical. What I am looking for are general considerations for combining a cartridge with an arm. I do not care much about question "what cartridge is the best for SME V" or anything like that. I do no believe in "the best for all times" because there can be many combinations with different results, many of them good. My worries are not to make some stupid things while experimenting and searching. Did not find much information on this one. However, while doing the search I found a good reference to Van Den Hul homepage where they have quite extensive FAQ in phono section. Some useful information can be found there at least to start with.
Actually you are trying to match the effective mass(different from weight) of the tonearm and compliance of the cartridge. You've chosen a very easy to match cartridge in the Shure, being a medium compliance piece. Look at this page for more insights-(http://www.theanalogdept.com/cartridge___arm_matching.htm).