.A cop car's siren has a frequency of 700 Hz, if you are standing on the sidewalk as the cop car approaches you at a speed of 15 m/sec, what frequency would you hear? 20 °C

732 Hz

Explanation:

Given the following :

Frequency (fs) of siren = 700Hz

Speed (vs) of approaching car = - 15m/sec

Velocity of listener(vl) = 0

Velocity of sound wave = 340m/s

From doppler effect, use the formula :

fl = [(v + vl) / (v + vs)] fs

Where fl is the frequency heard by the listener

fl = [(340 + 0) / (340 +(- 15) )] * 700

fl = [ 340 / 325] * 700

fl = 1.0461538 * 700

fl = 732.30769

fl = 732 Hz ( to the nearest whole number)

the service industry in the united states grew in the late 1800s. what was one effect of that growth?

the number of people with jobs in factories as unskilled workers decreased.

the number of people with jobs in factories as unskilled workers increased.

the middle class grew as people took jobs as clerks, lawyers, and teachers.

the middle class shrank as people left jobs as clerks, lawyers, and teachers.

a) walter looks unhealthy