Final answer:
The difference between slaved gyro and free gyro modes is that a slaved gyro is automatically aligned with the Earth's magnetic field while a free gyro operates independently of external references. Slaved gyros maintain accuracy without manual adjustments, whereas free gyros need periodic recalibration due to precession. Gyroscopes maintain a constant direction of angular momentum due to the conservation of angular momentum.
Step-by-step explanation:
When discussing the difference between "slaved gyro" and "free gyro" modes in the context of heading indicators or gyroscopes used in navigation, it is important to understand how gyroscopes function. A gyroscope contains a spinning disk where the axis of rotation can assume any orientation. Once spinning, the orientation of this spin axis is not influenced by the movement or orientation of the surrounding body, which is particularly useful in navigation systems where magnetic compasses are not functional, such as in spacecraft and satellites.
In slaved gyro mode, the heading indicator is automatically adjusted, or "slaved," to align with a magnetic direction reference, often through the use of magnetic sensors. This calibration ensures that the gyro's indication remains consistent with Earth's magnetic field, providing accurate directional information. Conversely, in free gyro mode, the heading indicator is not tied to any external reference. It operates independently and relies solely on the gyro's ability to maintain its orientation due to angular momentum. This means while in free gyro mode, there may be a drift due to precession, and manual adjustments or recalibrations are necessary periodically to ensure accuracy.
The ability of a gyroscope's angular momentum to remain constant despite forces and accelerations lies in the physical principle of conservation of angular momentum. Gyroscopes used in guidance systems maintain their orientation because of this principle, regardless of external forces acting upon them, which allows for stable direction indication in the control systems of various vehicles and devices in space and aviation.