Well the US doesn't naturally have a lot of fossil fuels so we rely on other countries who do have fossil fuels. So if we aren't that friendly with Saudia Arabia (they have a bunch of oil) then they can hike up the prices or cut us off from their oil supply completely which would cripple the US severly. So with that being said, we NEED other countries, and the big question is when will they not NEED us. At any point in which they feel that they don't need us they can just cut us off, which would be bad.
Hope that helps :)
If you were to sit a hot cup of water out side it would frezze faster
Answer:
The phase difference is 
Explanation:
From the question we are told that
The distance between the slits is
The distance to the screen is 
The wavelength is 
The distance of the wave from the central maximum is 
Generally the path difference of this waves is mathematically represented as

Here
is the angle between the the line connecting the mid-point of the slits with the screen and the line connecting the mid-point of the slits to the central maximum
This implies that

=> 
![\theta = tan ^{-1} [\frac{5*10^{-3}}{1}]](https://tex.z-dn.net/?f=%5Ctheta%20%3D%20tan%20%5E%7B-1%7D%20%5B%5Cfrac%7B5%2A10%5E%7B-3%7D%7D%7B1%7D%5D)

Substituting values into the formula for path difference
The phase difference is mathematically represented as

Substituting values

Converting to degree
the solution is subtracted by 360° in order to get the actual angle
Answer:
Density of 127 I = 
Also, 
Explanation:
Given, the radius of a nucleus is given as
.
where,
- A is the mass number of the nucleus.
The density of the nucleus is defined as the mass of the nucleus M per unit volume V.

For the nucleus 127 I,
Mass, M = 
Mass number, A = 127.
Therefore, the density of the 127 I nucleus is given by

On comparing with the density of the solid iodine,
