In which of the following will you (the observer) hear a higher frequency than w
ID: 1456728 • Letter: I
Question
In which of the following will you (the observer) hear a higher frequency than what the source is emitting? Choose all that apply. 1..A police car with its siren on is stationary. You are stationary.2... A fire truck with its siren on is moving away from you while traveling 40 mph. You are moving towards it while traveling 40 mph. 3...An ambulance with its siren on is moving towards you while traveling 50 mph. You are stationary. 4....A train with its horn blaring is circling you. You are stationary. 5...A marching band playing the 1812 Overture is moving towards you while traveling 50 ft/min. You are stationary.
Explanation / Answer
When the source is approaching, the frequency
f= [v/(v-vs)]* fsource
Vs is postive if relative distance between source and observere is getting less.
So answer to the question are.
A train with its horn blaring is stationary. You are moving towards it while traveling 50 mph.
A marching band playing the 1812 Overture is moving away from you while traveling 40 ft/min. You are moving towards it while traveling 50 ft/min.
Between, when source is encricling you, relative distance stays the same, vs=0. No frequency change.