Answer:
D. The frequency is not affected as the volume of sound increases
Explanation:
Volume of the sound is defined by the amplitude of the wave or how loud a sound is whereas Frequency is basically the pitch of the sound and is inversely proportional to the wavelength . Increasing frequency will increase the pitch of the sound without affecting it's volume.
The formula is M=Fd
so we have F=84N and d=0.25m
Now we just replace F and d into the formula M=84N×0.25m
And the last thing we do is calculate it
M=21Nm