Answer:
Brasil es un país de de Sudamérica
Explanation:
(Country)
My book is The Lord of the Rings.
Answer:
minimum speed to know if the whistle is working = 16.33m/s
Explanation:
Speed of sound, v= 343m/s
Hearing frequency of dog, f= 21kHz
Hearing Frequency of man, fₐ= 20kHz
Minimum travel speed, vₐ=?
Using the formula;
fₐ=(1-vₐ/v)f
20=(1-vₐ/343)21
(1-vₐ/343)=20/21
vₐ/343=1-0.9524
vₐ=0.0476*343
vₐ=16.33m/s
