What does the unit FT/SEC measure?

The unit FT/SEC, which stands for feet per second, is a measurement of speed. This unit indicates how many feet an object travels within one second. In the context of public health, understanding speed is crucial, particularly when assessing things like the flow rate of air in ventilation systems or the speed at which water moves in environmental studies. Recognizing the significance of speed as a measurement is essential in various public health settings, such as understanding the transmission rates of airborne pathogens or the effectiveness of water filtration systems.

Other options like weight, pressure, and volume do not relate to the unit FT/SEC, as these measurements pertain to different physical properties. Weight is measured in units like pounds or kilograms, pressure in pascals or psi, and volume in liters or gallons. Therefore, FT/SEC specifically quantifies speed, making it the correct answer to the question.