Clauses: I know the place where she works. I know where she works.

[Morteza]

Hi,
Could you please determine the grammatical function of "where" in the following sentences?Also,which type of clauses are they?I mean noun/adj/adv clauses:
I know the place where she works.
I know where she works.
You can stop where you want.
Many thanks,
Morteza

[Gray]

Adding one more question --

'Where' is an adverb. Which verb it describes here - the one that precedes it or the one that follows it?
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First lesson - English, not english. I, not i. ~A student of English

[Prezbucky]

I'll shoot first and let the bodies fall where they may.

1) I know the place where/at which/in which she works. (all three are okay)
2) I know where she works. (perfect-- this is, without question, the best way to promote this point of view)
3) Are we riding in a car or filling a cup?
Where = Place, geographic location, etc.
"Where are we going?"
"I thought that this was where we were supposed to stop."
"We're going where the cows graze and the fires blaze."

When = time/date or level (glass, fuel, etc.)
"When will this stop?"
"I don't know when I'll climb K2, but by God I will!"
"Tell me when to stop filling your glass... just say 'when'."
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Billie Jean is not my lover. Hee.