Energy that transfers through the medium
Answer:
As the sound approaches, it gets louder (simply because you're closer to the source), and has a higher pitch. Then, as it passes, the sound suddenly dips down, and as it drives away you hear a lower pitch, plus a decreasing volume as the engine gets farther and farther away.
Explanation:
I cannot see all the questions, what is 18,19 and 21? (:
Answer:
The inter-molecular forces holding non-polar compounds together is low compare to that of polar compounds. Therefore, it will take less energy to break the bond for non-polar compounds and vice versa. That is why polar compounds have higher melting points than non-polar compounds.
Explanation:
Answer:
The frequency of these waves is 
Explanation:
Given that,
Wavelength = 6.6 km
Distance = 8810 km
Time t = 8.67 hr
We need to calculate the velocity of sound
Using formula of velocity
Where, D = distance
T = time
Put the value into the formula
We need to calculate the frequency
Using formula of frequency
Put the value into the formula
Hence, The frequency of these waves is
