I believe it is water that is the medium for beach erosion
First choice: the inability of current technology to capture
large amounts of the
Sun's energy
Well, it's true that large amounts of it get away ... our 'efficiency' at capturing it is still rather low. But the amount of free energy we're able to capture is still huge and significant, so this isn't really a major problem.
Second choice: the inability of current technology to store
captured solar
energy
No. We're pretty good at building batteries to store small amounts, or raising water to store large amounts. Storage could be better and cheaper than it is, but we can store huge amounts of captured solar energy right now, so this isn't a major problem either.
Third choice: inconsistencies in the availability of the resource
I think this is it. If we come to depend on solar energy, then we're
expectedly out of luck at night, and we may unexpectedly be out
of luck during long periods of overcast skies.
Fourth choice: lack of
demand for solar energy
If there is a lack of demand, it's purely a result of willful manipulation
of the market by those whose interests are hurt by solar energy.
Acceleration of an object is depended upon the net force acting open the object and the mass of the object
Answer:
The mass of Uranium present in a 1.2mg sample is 
Explanation:
The ration between Uranium mass and total sample mass is: 
For a sample of mass 1.2 mg, the amount of uranium is:
Answer:
The amount of mass that needs to be converted to release that amount of energy is 
Explanation:
From Albert Einstein's Energy equation, we can understand that mass can get converted to energy, using the formula
where 
= change in mass
c = speed of light = 
Making m the subject of the formula, we can find the change in mass to be
There fore, the amount of mass that needs to be converted to release that amount of energy is 1.122 X 10 ^-7 kg
