This is a clumsy and ambiguous sentence. Were YOU sleeping when you woke up the man? The use of the definite article (the) implies that there were a lot of men in the room but only one was sleeping and you woke him up.
2-I woke up a man sleeping.
This is also clumsy and ambiguous. But it implies that there were many men in th
So ,you mean you woke up the sleeping man and then sleeping man fell off his chair. Why did you weak him up in the first place? He might have been having wonderful dreams. Is this sentece correct? I mean the last sentence.