To solve this problem it is necessary to apply the concepts related to Sound Intensity. The unit most used in the logarithmic scale is the decibel and mathematically this is expressed as

Where,
= Sound intensity level in decibels
I = Acoustic intensity on the linear scale
Hearing threshold
According to the values, the total intensity is 32 times the linear intensity and the value in decibels is 83dB
So:




Therefore the sound intensity due to one person is 67.948dB
Answer:
b- a bicycle sitting on the ground
Explanation:
'Static' means it's not moving.
So, only the answer listed as "a bicycle sitting on the ground" corresponds to that condition.
All others possible answers describe something that is moving (an apple falling, a motorcycle accelerating, a car moving at a constant speed). Even if they are going at a constant speed, they are moving, so not static.
Answer:
2 seconds
Explanation:
The frequency of a wave is related to its wavelength and speed by the equation

where
f is the frequency
v is the speed of the wave
is the wavelength
For the wave in this problem,
v = 2 m/s

So the frequency is

The period of a wave is equal to the reciprocal of the frequency, so for this wave:

This means that the wave takes 4 seconds to complete one full cycle.
Therefore, the time taken for the wave to go from a point with displacement +A to a point with displacement -A is half the period, therefore for this wave:
