Consider a cloudless day on which the sun shines down across the united states. if 2529 kj of energy reaches a square meter (m2) of the united states in one hour, how much total solar energy reaches the entire united states per hour? the entire area of the united states is 9,158,960 km2 .

2.31 10^16 kJ

Explanation: The entire area of USA is 9158960*1000m*1000m=

9.16*10^12 m^2

So the total energy receibed from the sun in whole USA is:

E totalUSA= Area USA * 2529kJ=2.31 10^16 kJ

whre 2529kJ is energy given by the sun per square meter.

We want to know how much solar energy reaches the total US's surface area in one hour, we will find that the answer is 23,163 kJ.

So we know that in each square meter per hour, there are:

2,529 kJ of energy.

So the energy per area is given as:

e = 2,529 kJ/m^2

We know that the total surface area of the US is:

A = 9,158,960 km^2

Notice that the area units are different, then we need to rewrite this, let's find the solar energy that reaches each square kilometer.

We know that:

1km = 1,000m

Then:

1km^2 = (1,000m)*(1,000m) =  1,000,000 m^2

Then the energy that reaches each square kilometer is given by:

e = (2,529 kJ/km^2)/(1,000,000) = 0.002529 kJ/km^2

Now, the total energy that reaches the entire United States per hour is given by the energy that reaches a single square kilometer times the total surface area, we have:

Total energy = (0.002529 kJ/km^2)*(9,158,960 km^2) = 23,163 kJ

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one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.