Question

Consider a cloudless day on which the sun shines down across the United States. If 2014 kJ of energy reaches a square meter( m 2) 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 km 2 .

Answer 1

Answer:

      $\large\boxed{\large\boxed{18,450kJ/hour}}$

Explanation:

1) Radiation's ratio: 2014 kJ/m²

2) United States' area:  is 9,158,960 km² .

3) Formula:

• Energy = ratio × area

4) Conversion factor:

         $(1km)^2=(1,000m)2\\\\1km^2=1,000,000m^2\\\\1=1km^2/1,000,000m^2$

5) Solve:

In one hour:

             $E=2,014kJ/m^2\times 9,158,960km^2\times 1km^2/1,000,000m^2\\\\E=18,446kJ\approx 18,450kJ$

That is per hour.

The answer is rounded to 4 signficant figures.