What type of interaction will change the waves speed the most reflection and refraction diffraction or interference

Which safety measures should you follow during a thunderstorm? check all that apply. (a) avoid touching anything that conducts electricity. (b) avoid touching a person who has been struck by lightning. (c) go outside. (d) keep your computer turned off. (e) stay out of water. (f) stay inside.

An object moves from position +34m to the position -15m in 15 seconds. what is the total displacement? what is the total velocity?

The frequency of the fundamental of the guitar string is 320 hz. at what speed v do waves move along that string?