There is a possessive case pronoun. As usual for such pronouns, it functions as an adjective in the sentence.
part of speech
Adjective
What part of speech is thaw
The part of speech for oscillate is verb.
An adjective is a part of speech.
what part of speech is work
It is a command; do is in the imperative.
Work is a verb in that example.
noun
It depends on how you are using the word. Work can be a noun (He was late for work) and a verb (How do you work this thing). With an ending, it can also be an adjective (It was a working part).
Worked is a verb. It is the past tense of work
part of speech
The part of speech for this particular word is a noun.
adverb
what part of speech is beneath
It depends on how you are using the word. Work can be a noun (He was late for work) and a verb (How do you work this thing). With an ending, it can also be an adjective (It was a working part).
"Worked" is the past tense or past participle of the verb "work".