gen-define-the-jet-stream-and-give-one-short-worked-example-da7f

Define the jet stream and give one short worked example.

# Jet Stream **Definition:** A jet stream is a narrow band of strong, fast-flowing air currents found in the upper atmosphere (typically 9-16 km altitude), moving from west to east in a meandering pattern. These rivers of air are caused by the combination of Earth's rotation and temperature differences between air masses, with wind speeds typically reaching 100-200+ mph. ## Worked Example **Problem:** A plane flies from New York to London (3,500 miles) at an airspeed of 500 mph. On the return flight, conditions are identical except for the jet stream. If the jet stream provides a 100 mph tailwind eastbound and a 100 mph headwind westbound, how much time is saved flying eastbound? **Solution:** *Eastbound (NY → London) with tailwind:* - Ground speed = 500 + 100 = 600 mph - Time = 3,500 miles ÷ 600 mph = **5.83 hours** *Westbound (London → NY) with headwind:* - Ground speed = 500 - 100 = 400 mph - Time = 3,500 miles ÷ 400 mph = **8.75 hours** **Time saved = 8.75 - 5.83 = 2.92 hours (about 2 hours 55 minutes)** This demonstrates why flights from North America to Europe are typically shorter than the reverse journey.