What are words that involve waves (amplitude, energy, frequency, etc)

Astring that is fixed at both ends has a length of 1.05 m. when the string vibrates at a frequency of 91.0 hz, a standing wave with five loops is formed. (a) what is the wavelength of the waves that travel on the string? (b) what is the speed of the waves? (c) what is the fundamental frequency of the string?

The place you get your hair cut has two nearly parallel mirrors 6.00 m apart. as you sit in the chair, your head is 2.00 m from the nearer mirror. looking toward this mirror, you first see your face and then, farther away, the back of your head. (the mirrors need to be slightly nonparallel for you to be able to see the back of your head, but you can treat them as parallel in this problem.) how far away does the back of your head appear to be?

Awave is produced in a rope. the wave has a speed of 33 m/s and a frequency of 22 hz.