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.
Answer: 
Explanation:
Given
Initial angular speed is 
Final angular speed is 
Time period 
Magnitude of the fan's acceleration is given by

Insert the values

Thus, fan angular acceleration is 
Answer:
Explanation:
The work increased the potential energy
W = PE = mgh = 40(9.8)(15) = 5880 J(oules)
D. distance
A light-year is the distance light would travel in 1 year.