Question

which instrument families are heard in this excerpt? which are not? haydn: trumpet concerto, excerpt 0:34 heard in excerpt strings woodwinds keyboard brass percussion (timpani)

Explanation:

The trumpet is a brass - instrument. In a trumpet concerto, the brass family (trumpet) is likely to be heard. Strings, woodwinds, keyboard and percussion (timpani) may or may not be present depending on the orchestration. Since it's a trumpet concerto excerpt, brass is very likely to be heard. Without actually listening to the excerpt, we can't be sure about the others, but strings, woodwinds, keyboard and percussion are not as certain as brass for a trumpet - focused piece.

Answer:

Heard in excerpt: brass
Not heard in excerpt (assumed without listening): strings, woodwinds, keyboard, percussion (timpani)