A solid substance melts at -21°C. If the object is known to change phase at 81°C, will the object be a solid, liquid, or gas at 90°C?

This section of the U.S. Army's SIFT (Selection Instrument for Flight Training) exam tests your knowledge of basic physics, electrical, and mechanical theories.

Mechanical Comprehension questions focus on topics such as force, friction, current, fluid, pressure, pulleys, gears, screws, engines, and other machine operations.  You must familiarize yourself with physics, basic electronics, and mechanics concepts.