Kaplan test 3 question 59

[applerotty]

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Hi, I am taking Kaplan test 3 and reviewing my answers and I am stuck on this question 59. Nowhere in the passage does it talk about air intake velocity, volume, or pressure. Am I missing something? Please help. Thanks!

Which of the following conditions must be true for the thrust fan to propel the hovercraft horizontally? (assume air is not compressed in the process).

A. the air intake velocity must be lower than the air output velocity.
B. the air intake velocity must be greater than air output velocity.
C. the air intake volume must be lower than the air output volume.
D. the air intake pressure must be greater than the air output pressure.

 

[Cmdr_Shepard]

Think about fluid concepts. Flow rate and the continuity equation. And also think about the principles behind laminar flow.

Imagine the scenario for each answer choice and see which ones break the fluid rules.