As far as "Long u" vowels you will also see that the u_e comboination, ew, and oo can make the same sound as a standard long u. Did you know the noun with the longest number of letters? It's a hill in New Zealand. It is called: Taumatawhakatangihangakoauauotamateaturipukakapikimaungahoronukupokaiwenuakitnatahu. Come on Kiwi-land you couldn't curb the letters, just a bit?
The most common long a words are: music, student, use, cute, huge, tube, rule and flute. The most common short a words are: bud, bug, cut, cup, fun, jug, run and tug.