Answer:
u=speed, w=wavelenght, f=frequency
It's known that u=w*f => f=u/w
u=20m/s ==> f=20/0,5 => f=40 Hz
w=0,50m
Explanation:
The answer is A bc I did the quiz and I got it right
Well, in some systems the atoms melt or burn or change state like from liquid to gases when they reach a certain temperature. This could decrease the energy in the system.
Hope I helped
