Answer:
-3.396 m/s or 3.465 m/s
Explanation:
v = Speed of sound in air = 343 m/s
= Relative speed of the singer
f = Observed frequency
f' = Actual frequency
1% change can mean 
From the Doppler effect equation we have

The velocity is -3.396 m/s
when 

The velocity is 3.465 m/s
They dont work because you crushed them duh
Answer:
C. It helps scientists detect dark matter.
Explanation:
I got a 100% on my test. hope it help and I hope your having an awesome day :)
<span>79.75m/s .................................</span>