When you turn on a fan its electrical energy changes into kinetic energy
<span>Self-fulfilling prophecy is a primary example of the capability of language to
Influence.</span>
Answer:
far from the speaker the intensity drops to 85 dB.
Explanation:
In the equation for the Decibel scale
The ratio of the intensities can be written as
And since
and
,
meaning
Putting this into equation (1), we get:
Now, if the intensity is 100 dB when the distance is 5 meters, we have:
by taking both sides to the exponent:
Now equation (2) becomes
when the intensity level is 85 dB we have
take both sides to exponents and we get:
Thus, far from the speaker the intensity drops to 85 dB.
The time taken by traveler to cover the distance is,
Substitute the known values,
Therefore, the time taken by traveler to cover the distance is 89.3 s.