32. A sound wave is 
a. a longitudinal wave*
b. a transverse wave
c. always a standing wave
d. nota
33. Sound travels fastest in
a. air
b. water
c. steel*
d. a vacuum
e. nota
34. The speed of a sound wave in air depends on
a. its frequency
b. its wavelength
c. the air temperature*
d. nota
35. Sound travels faster in air if the air temperature is (a) warm*   (b) cold    (c) average 
FOR BACKGROUND ON THE FOLLOWING PROBLEM, READ PAGE 359-361, WITH AN  EYE ON RESONANCE.  When you feed a system with energy at the natural frequency, the amplitude of vibrations grows large, to the point where the motion  surpasses the  elastic limit and the structure comes apart. See figure 20.15 of the  Tacoma Narrows Bridge.
36. The natural frequency of an empty wine glass is 256 Hz. The glass will resonate if the vibrating force due to the sound of a nearby opera singer is (a) 512 Hz   (b) 256 Hz*   (c) 1024 Hz  (d) nota