Answer asap for 40 points

the doppler effect is the result of a sound source that causes the sound to appear higher or lower than its true as a sound source approaches an observer, the distance between each in the wave is this causes a perceived pitch. as a source moves away from an observer, the distance between each crest in the wave is this causes a perceived pitch. the size of the pitch is determined by the speed of the source relative to the speed of

word bank

higher
shift
increased
moving
lower
pitch
sound
crest
shortened