Fundamentals of Engineering FE Knowledge 4 — Questions and Answers
Question 1: A 3 Ω and 6 Ω resistor are connected in parallel. What is the equivalent resistance?
- 9 Ω
- 4.5 Ω
- 2 Ω (Correct answer)
- 0.5 Ω
Correct answer: 2 Ω
1/R_eq = 1/3 + 1/6 = 2/6 + 1/6 = 3/6, so R_eq = 2 Ω.
Question 2: Which of the following dimensionless numbers represents the ratio of inertial forces to viscous forces in fluid flow?
- Froude number
- Mach number
- Reynolds number (Correct answer)
- Weber number
Correct answer: Reynolds number
The Reynolds number Re = ρVL/μ is the ratio of inertial to viscous forces and determines flow regime.
Question 3: What is the determinant of the matrix [[2,1],[3,4]]?
- 5 (Correct answer)
- 8
- 11
- 14
Correct answer: 5
det = (2)(4) − (1)(3) = 8 − 3 = 5.
Question 4: During an isentropic process, which pair of properties remains constant?
- Temperature and pressure
- Entropy and heat transfer
- Entropy (constant) with no heat transfer (Correct answer)
- Enthalpy and volume
Correct answer: Entropy (constant) with no heat transfer
An isentropic process is both adiabatic (no heat transfer) and reversible, so entropy remains constant.
Question 5: A 10 kg block rests on a 30° incline with μ_s = 0.4. What is the maximum static friction force available (g = 9.81 m/s²)?
- 19.62 N
- 34.0 N (Correct answer)
- 39.2 N
- 49.0 N
Correct answer: 34.0 N
Normal force N = mg cos30° = 10×9.81×0.866 = 84.9 N; f_s_max = μ_s × N = 0.4×84.9 ≈ 34.0 N.
Question 6: The continuity equation in fluid mechanics is an expression of:
- Conservation of momentum
- Conservation of mass (Correct answer)
- Conservation of energy
- Newton's second law
Correct answer: Conservation of mass
The continuity equation ∂ρ/∂t + ∇·(ρV) = 0 enforces conservation of mass in fluid flow.
Question 7: If a project has a benefit-to-cost ratio (BCR) of 1.35, which statement is correct?
- The project should be rejected because costs exceed benefits
- The project breaks even exactly
- The project is economically justified because benefits exceed costs (Correct answer)
- The BCR must equal 2.0 to be acceptable
Correct answer: The project is economically justified because benefits exceed costs
A BCR > 1.0 indicates the present worth of benefits exceeds costs, making the project economically justified.
Fundamentals of Engineering FE Knowledge 4
A 3 Ω and 6 Ω resistor are connected in parallel.
What is the equivalent resistance?