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.
Resolving Forces into Components: FE Civil practice problem 5
During a submittal reconciliation for the Canyon Mesa water main crossing pavement preservation project, the resident engineer resolves a 360 lb cable force acting 25 degrees above horizontal. What is the horizontal component?
- A364.6 lb
- B407.2 lb
- C494.5 lb
- D326.3 lb
Show the answer and worked solution
Answer: D — 326.3 lb
Worked solution
- Step 1. Use the cosine component
F_x = F cos theta
- Step 2. Substitute values
F_x = 360 cos(25 deg) = 326.3 lb
Why the other choices are wrong
- Choice A
- This value cannot be reproduced by a single clean trigonometric slip in resolving the 360 lb tension; the horizontal component is found from F_x = F*cos(theta) = 360*cos(25 deg) = 326.3 lb, and no simple sine-cosine swap or angle-complement error lands on this number.
- Choice B
- No identifiable one-step mistake in the cosine resolution accounts for this figure; the correct horizontal pull follows from F_x = F*cos(theta), which gives 360*cos(25 deg) = 326.3 lb, so this result does not trace back to one defensible calculation error.
- Choice C
- This number is not the product of one obvious miscalculation such as swapping sine for cosine or misreading the angle; applying F_x = F*cos(theta) to the 360 lb force at 25 degrees above horizontal correctly yields 326.3 lb.