Aphysics professor demonstrates the doppler effect by tying a 600 hz sound generator to a 1.0-m-long rope and whirling it around her head in a horizontal circle at 120 rpm. assume the room temperature is 20 degrees celsius.

part a: what is the highest frequency heard by a student in the classroom? (in hz)

part b: what is the lowest frequency heard by a student in the classroom? (in hz)

(a) f= 622.79 Hz

(b) f= 578.82 Hz

Explanation:

Given Data

Frequency= 600 Hz

Distance=1.0 m

n=120 rpm

Temperature =20 degree

Before solve this problem we need to find The sound generator moves on a circular with tangential velocity

So

Speed of sound is given by

c = √(γ·R·T/M) in an ideal gas

where γ heat capacity ratio

R universal gas constant

T absolute temperature

M molar mass

The speed of sound at 20°C is

c = √(1.40 ×8.314472J/molK ×293.15K  / 0.0289645kg/mol)

c= 343.24m/s

The sound moves on a circular with tangential velocity

vt = ω·rwhere   ω=2·π·n

vt= 2·π·n·r

vt= 2·π · 120min⁻¹ · 1m

vt= 753.6 m/min  

convert m/min to m/sec

vt= 12.56 m/s

Part A

For maximum frequency is observed  

v = vt

f = f₀/(1 - vt/c )

f= 600Hz / (1 - (12.56m/s / 343.24m/s) )  

f= 622.789 Hz

Part B

For minimum frequency is observed

v = -vt

f = f₀/(1 + vt/c )

f= 600Hz / (1 + (12.56m/s / 343.24m/s) )

f= 578.82 Hz

it doesn't. it was imagined up in the middle ages.

i had this question and the answer was 3.15 miles.

martina travels from school to her mom's office. from there, she walks to school. after school, she walks to the library and then to a friends house before finally ending back at home. find martina's total distance traveled.

a) 0 miles  

b) 0.4 miles  

c) 1 mile  

d) 3.15 miles