grammar - Two questions about the verb "knock"

Consider (Source):

1. A goldfinch flew across the field, struck the glass and was knocked inert.


2. The large birds flew together and struck the glass; they were knocked into a stupor.

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Question 1 : Would you tell me how the adjective can be used after verb in sentence #1? I am saying that since I never saw the verb knock being used as a linking verb.

Question 2: As far as I know, stupor is a state and knock someone into something means to make someone strike something. Has the verb knock used figuratively? I want to know more about it.