Information Systems Technician Second Class (IT2) Advancement Practice Exam

The speed of sound in air depends on temperature: as air gets colder, molecules move more slowly and sound travels more slowly; warmer air lets sound propagate faster. For air, the speed can be estimated with a = sqrt(gamma * R * T), where gamma is about 1.4 for dry air, R is 287 J/(kg·K), and T is the absolute temperature in kelvin.

At 32 degrees Fahrenheit, the air is at 0 degrees Celsius, which is 273.15 K. Plugging in the values gives a ≈ sqrt(1.4 * 287 * 273.15) ≈ 331 m/s. Converting to feet per second (1 m/s ≈ 3.281 ft/s) yields about 1087 ft/s. So the speed of sound in air at 32 °F is around 1087 ft/s.

For context, at typical room temperature (about 20 °C) it’s about 343 m/s (roughly 1125 ft/s), illustrating how temperature shifts the speed.