Final answer:
Vacuum operated gyro instruments use gyroscopes to maintain a constant orientation of angular momentum, helping to provide directional guidance in vehicles where traditional navigation means are not viable. Despite any forces or accelerations, the instruments' angular momentum remains stable due to the conservation of angular momentum and limited external torque.
Step-by-step explanation:
Vacuum Operated Gyro Instruments
Vacuum operated gyro instruments are essential in modern aviation and spacecraft navigation systems. They utilize a gyroscope, which comprises a rapidly spinning disk where the axis of rotation is free from the influence of any forces outside the system, maintaining a constant orientation in space. Despite a vehicle's movements or changes in orientation, the spinning disk - or gyro - remains stable. This stability is crucial for providing accurate directional guidance, making them indispensable in environments where magnetic compasses are unreliable, such as space.
The functioning of a gyroscope in the context of gravity and relativity theory is fascinating. As demonstrated in the Gravity Probe B spacecraft, gyroscope instruments pointed at a star while in Earth's orbit will experience minute deviations in spin direction due to Earth's gravity, as predicted by relativity. These deviations are incredibly small but critical for precision navigation and confirming scientific theories.
As for why the angular momentum of gyroscopes remains constant even under acceleration, it is due to the physical properties of angular momentum itself. Angular momentum is conserved in a system unless acted on by an external torque. Since the gimbals of the gyroscope permit it to rotate freely, and the vacuum operation reduces friction and external forces, the axis of rotation remains fixed in direction, regardless of the accelerations applied to the enclosing body.