Final answer:
The three instruments connected to the pitot-static system are the airspeed indicator, altimeter, and vertical speed indicator. They rely on pitot tubes and manometers to determine aircraft speed, altitude, and climb/descent rates using principles such as Bernoulli's.
Step-by-step explanation:
The three pressure instruments connected to the pitot-static system are the airspeed indicator, the altimeter, and the vertical speed indicator (VSI). These instruments rely on the measurement of pressure differences. The airspeed indicator measures the speed of an aircraft through the air by comparing ram pressure from the pitot tube with the static pressure from the static port. The altimeter uses static pressure to determine the aircraft's altitude above sea level. The VSI indicates whether the aircraft is climbing, descending, or in level flight based on the rate of change of static pressure.
Devices like the manometer and the Prandtl tube, more commonly known as a pitot tube, are essential tools in measuring pressure and fluid speed. Bernoulli's principle plays a vital role in determining the relationship between the velocity of fluid and pressure changes within these instruments. Specifically, for pitot tubes, the difference in height (h) of the fluid column in the manometer is proportional to the square of the velocity (v), which in turn affects the pressure reading being measured.