Drag the observer onto the road. Click Play, and then click Pause when the sound waves first reach the observer. What is the frequency of sound waves in front of the plane?

3.2x10^7

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.