Gyro instruments are based on which two principles?

Gyro instruments operate on the principles of rigidity in space and inertia. Rigidity in space refers to the tendency of a spinning object (such as a gyroscope) to maintain its orientation regardless of the motion of the platform it's mounted on. This property allows gyro instruments to provide stable references for navigation and attitude. As an aircraft turns, for example, the gyroscope remains fixed in its orientation, allowing pilots to have accurate information about their airplane's position relative to the horizon.

Inertia, on the other hand, is the resistance of an object to change its state of motion. This principle also plays a critical role in how gyro instruments function. When a gyroscope is set in motion, it will resist any change to its axis of rotation. This inertia allows gyroscopic instruments to provide readings that are unaffected by the aircraft’s movement, helping to ensure stable and reliable instrument indications.

The other provided principles—speed and altitude, pressure and rotation, and acceleration and gravity—do not directly relate to the operational characteristics of gyro instruments, thus further validating the choice focused on rigidity in space and inertia as the foundation of gyro technology.