Repeat the calculation of Example 4.2 in Engineering English units. Check that your answers agree with the solution in Example 4.2 using the appropriate conversion factors.

Example 4.2

Estimate the total kinetic energy of the wind on the Earth. As an introduction to this problem, consider that the wind is a movement of air that is produced by temperature differences in the atmosphere. Since hot air is less dense than cold air, air heated by the Sun at the equator rises until it reaches an altitude of about 6.0 miles (9.0 km) and then it spreads north and south. If the Earth did not rotate, this air would simply travel to the North and South Poles, cool down, and return to the equator along the surface of the Earth as wind. However, because the Earth rotates, the prevailing winds most of us see travel in a west–east rather than a south–north direction (in the northern hemisphere). In places where winds are strong and steady, it may make economic sense to install a windmill or wind turbine to capture that translational kinetic energy.