History Quiz: Date Reference Questions

Study Notes

Newton's first law is known as the law of inertia, illustrating an object's resistance to changes in motion.
When a mass of air is accelerated rearward, a forward reaction (thrust) occurs according to Newton's third law.
Analyzing airflow in an axial compressor treats velocity as a vector quantity, which includes both magnitude and direction.
Velocity differs from speed by incorporating direction in its measurement, while speed is a scalar quantity.
A spring possesses potential energy, which is the stored energy due to its position.

Total pressure in a fluid system is the sum of static pressure and dynamic pressure.
Inlet air total pressure experiences an increase in ram air, enhancing engine power due to increased static pressure and air density.
Total air pressure measured at static pressure adds the ram effect, impacting overall pressure readings.
When airflow passes through a convergent duct, it results in a pressure drop, velocity rise, and temperature drop, applicable only for subsonic airflow.
Diffuser inlets are characterized by a pressure rise, temperature rise, and velocity drop.
Airflow through a divergent duct leads to a pressure rise, temperature rise, and velocity drop for subsonic airflow.

The aerodynamics between compressors and turbines varies significantly: compressors have converging passages while turbines utilize diverging passages.
Air exiting from a choked nozzle experiences pressure above ambient conditions, attributable to increased upstream total pressure.
An exhaust nozzle speed exceeds Mach 1 if the pressure ratio of an engine surpasses 1.89, indicating significant air velocity changes.
A choked nozzle provides pressure thrust, enhancing overall thrust performance by utilizing excess pressure in the propelling nozzle.

Choked nozzles add thrust by converting pressure energy into kinetic energy, resulting in increased velocity at the exit—critical for optimizing engine performance.