I created this set of practice problems for my high school physics class. We use this when we study open/closed pipes and resonance on strings.
This includes 6 practice problems with space for students to work out their answers. A detailed key is provided. This saves you time but also allows your students to see exactly where they are having problems. The last problem is a challenge problem for advanced students to try once they've mastered the other problems.
I use this to teach the following Georgia Performance Standard:
SP4. Students will analyze the properties and applications of waves.