"effective mass" is an arm manufacturer's spec. - just ask them.
Then read this link, & browse around all the other analog features on this site for a better understanding:
http://www.gcaudio.com/Archives/tonearmcartidge.htm
Then read this link, & browse around all the other analog features on this site for a better understanding:
http://www.gcaudio.com/Archives/tonearmcartidge.htm