The problem is basically asking us to find a way to find the sound intensity I, in terms dependent on the sound level and the reference intensity 
.For this purpose we can start from the unit used in the scale logarithmic decibel, that is
Where
I = Acoustic intensity on the linear scale
Hearing threshold
Using the logarithmic properties of the exponents the above expression can be described as:
that is the expression or technique to find the intensity of sound.
Ware them down, its like rubbing two pieces of chalk together.
Answer:
The mass of the object, its acceleration due to gravity and the distance between the top of the hill and the ground level.
Explanation:
gravitational potential energy is the energy possessed by a body under influence of gravitational force by virtue of its position.
In order to determine the gravitational potential energy of the brick, we must know the mass (m) of the brick, its acceleration due to gravity (g) since it is acting under the influence of gravitational force and the distance between the top of the hill and the ground level. (The height).
Potential energy of a body is calculated as mass × acceleration due to gravity × height.
Answer:
PO(1) = PO(0) / 2 1 refers to 1 half life of PO(0)
PO(2) = PO(1) / 2 = P(0) / 4 amount of PO left after 2 half-lives
PO(3) = PO(2) / 2 = PO(0) / 8 amount of PO left after 3 half-lives
414 da / 138 da = 3 3 half-lives pass in 414 da
PO(0) = 8 PO(3) = 8 * 1.45E-4 g = 1.16E-3 g = .00116 g after 414 days
