an ambulance is traveling at $85$ mph the frquency of sound emitted is $8080$ hz$.$ what is the sound frequency you hear as it approaches? what is the sound frequency as it pulls away? if this were light from a distant green star $($f$=5\mathrm{.}66$ x $1014$ s $-1)$ moving away from you at $0\mathrm{.}25$ times the speed of litht, approximately what color of light what you perceive the star to be$?$