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 1
For the West Basin retaining wall replacement, a project engineer preparing an agency resubmittal package resolves a 480 lb cable force acting 50 degrees above horizontal. What is the horizontal component?
- A337.9 lb
- B399.3 lb
- C446.9 lb
- D308.5 lb
Show the answer and worked solution
Answer: D — 308.5 lb
Worked solution
- Step 1. Use the cosine component
F_x = F cos theta
- Step 2. Substitute values
F_x = 480 cos(50 deg) = 308.5 lb
Why the other choices are wrong
- Choice A
- This value is slightly above the horizontal component from F cos(theta) for a 480 lb cable force at 50 degrees above horizontal; it does not match multiplying 480 by the cosine of 50 degrees, so F_x should be recomputed directly from the stated force and angle.
- Choice B
- This value is moderately below the horizontal component from F cos(theta) for a 480 lb cable force at 50 degrees above horizontal; it does not match multiplying 480 by the cosine of 50 degrees, so F_x should be recomputed directly from the stated force and angle.
- Choice C
- This value is well above the horizontal component from F cos(theta) for a 480 lb cable force at 50 degrees above horizontal; it does not match multiplying 480 by the cosine of 50 degrees, so F_x should be recomputed directly from the stated force and angle.