He 40th parallel of north latitude runs across the United States through Philadelphia, Indianapolis, and Denver. At this latitude, Earth's radius is about 3030 miles. The earth rotates with an angular velocity of _π_ radians (or 15°) per 12 hour toward the east. If a jet flies due west with the same angular velocity relative to the ground at the equinox, the Sun as viewed from the jet will stop in the sky. How fast in miles per hour would the jet have to travel west at the 40th parallel for this to happen?