When writing North in Hiragana would I use "tsu" or "su"?

You would use the KATAKANA for "SU" NORTH = ノース

For example, North Carolina State University is translated as ノースカロライナ州立大学

If you haven't learnt Katakana (which I think you should for a 101 class) the hiragana would be のーす

Since it's a foreign word, "north" would normally be written in katakana, like this: ノース

If you haven't learned katakana yet, you can write it in hiragana: のーす　

North = noosu

"su" and "tsu" are different pronunciations.

Press them here.

http://www.saiga-jp.com/pronunciation_voice.html

"North" is pronounced "Noosu" in Japanese.