Question

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

Explanation:

The excerpt is from Haydn's Trumpet Concerto. Trumpet is a brass - instrument. So brass is heard. Without listening to the full excerpt, we assume other families are not heard.

Answer:

Heard in excerpt: brass
Not heard in excerpt: woodwinds, percussion (timpani), strings, keyboard