It is true that constructive interference will cause two sound waves to cancel each other out resulting in silence.
Everything in the universe that is not a star reflects light from Stars. Otherwise you can't see it.
Answer:
t=4.86s
Explanation:
To find the wavelength you use the following formula:

v: speed of sound = 343m/s
f: frequency = 400Hz
λ: wavelength of the sound
By doing λ the subject of the formula and replacing the values of f and v you obtain:

Now, to calculate the time that sound takes to reach the last row you use:

t: time
d: distance to the last row = 1947m

hence, the time is 4.86s
Answer:
Work done= Energy transferred
Explanation:
Work is the transfer of energy. In physics we say that work is done on an object when you transfer energy to that object. If you put energy into an object, then you do work on that object (mass).