Answer:

Explanation:
speed of bat = 6 m/s
sound wave frequency emitted by bat = 30.0 kHz
as we know,
speed of sound (c)= 343 m/s



now frequency received by bat is equal to



hence the frequency hear by bat will be 29.98 Hz
D. 100 kilometers cuz the more kilometers the better the altitude!!!
To find work, you use the equation: W = Force X Distance X Cos (0 degrees)
Following the Law of Conservation of Energy, energy cannot be destroyed nor created.
So you would do 75 N x 10m x Cos (0 degrees)= 750 J