Original question written by FE Exam AI Prep from the public FE Civil exam specification. Before release, a solver model re-derived the answer twice from the question alone, without its answer key, and a critic model checked the result, and the arithmetic was re-run as an executable calculation. No licensed engineer reviews these questions. It is not an NCEES question and does not come from any NCEES practice exam. FE Exam AI Prep is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCEES.
Hydrostatic Pressure: FE Civil practice problem 3
For the Harbor District industrial service road, a survey coordinator preparing a permit comment response converts a water pressure head of 16 ft to psi. Use gamma = 62.4 lb/ft^3 and 144 in^2/ft^2. What pressure is equivalent?
- A4.66 psi
- B5.57 psi
- C6.93 psi
- D6.06 psi
Show the answer and worked solution
Answer: C — 6.93 psi
Worked solution
- Step 1. Convert head to pressure
p = gamma h / 144
p = 62.4(16)/144 = 6.93 psi
Why the other choices are wrong
- Choice A
- This value is roughly twenty-two percent below the correct pressure and does not follow from one clean, traceable conversion mistake; working p = gamma * h / 144 through with the stated unit weight and head gives the correct, higher psi result.
- Choice B
- This choice is roughly forty-five percent above the correct pressure and does not reduce to one identifiable conversion error; carrying out p = gamma * h / 144 directly with the stated unit weight and head instead produces the true, lower psi value.
- Choice D
- This option is roughly eighteen percent above the correct pressure and cannot be tied to a single defensible arithmetic or unit slip in the head-to-pressure conversion; substituting the given unit weight and head into p = gamma * h / 144 produces the correct, lower psi answer.