Mixed Deck — All NCEES Topics Flashcards

A PE is asked to sign off on a structural analysis report that used assumptions she considers overly optimistic but technically within code limits. She should:

Answer: Sign after documenting her concerns and ensuring the assumptions are defensible

A PE may sign reports containing debatable but defensible engineering judgments, provided she documents her evaluation and is satisfied the assumptions meet applicable standards.

Two masses, 3 kg and 7 kg, are connected by a string over a frictionless pulley (Atwood machine). What is the acceleration of the system?

Answer: 3.92 m/s²

a = (m2−m1)g/(m1+m2) = (7−3)×9.81/10 = 3.92 m/s².

A state engineering board typically has the authority to do which of the following?

Answer: Revoke, suspend, or place conditions on a PE license

State engineering boards are regulatory agencies empowered to discipline licensees, including revoking or suspending PE licenses for violations of the practice act.

A project requires $200,000 now and yields $50,000/year for 6 years. At MARR = 10%, (P/A,10%,6)=4.3553, the net present value is:

Answer: $17,765

NPV = −200,000 + 50,000(4.3553) = −200,000 + 217,765 = +$17,765.

On the NCEES PE Environmental exam, the biochemical oxygen demand (BOD) test measures:

Answer: The amount of dissolved oxygen consumed by microorganisms in degrading organic matter

BOD measures the dissolved oxygen consumed by aerobic biological organisms decomposing organic material in water at 20°C over 5 days.

A Carnot refrigerator operates between −20°C and 30°C. What is its coefficient of performance (COP)?

Answer: 5.06

COP_refrigerator = T_L/(T_H − T_L) = 253/(303−253) = 253/50 = 5.06.

In NCEES test preparation, what is the best approach to estimation problems?

Answer: Round to manageable numbers and calculate approximate answers

Rounding to manageable numbers allows quick approximate calculations that can verify reasonableness of answers or eliminate incorrect choices.

A system undergoes a process where ΔU = 200 kJ and Q = 350 kJ. Using the first law, what is the work done BY the system?

Answer: 150 kJ

First law: Q = ΔU + W → W = Q − ΔU = 350 − 200 = 150 kJ (work done by the system).

A PE who signs a document as the engineer of record is taking personal professional responsibility for:

Answer: The entire engineering work represented by that document

The engineer of record accepts full professional responsibility for all engineering content within the document bearing her seal, not just portions she personally drafted.

A geometric gradient series has a first payment of $1,000 and increases by 5% each year for 4 years at i = 10%. What is the present worth? (P/G, geom formula: P = A₁[(1−(1+g)ⁿ(1+i)⁻ⁿ)/(i−g)])

Answer: $3,397

Using the geometric gradient PW formula with A₁=$1,000, g=5%, i=10%, n=4, PW ≈ $3,397.

What is the value of continuing education in statics for NCEES professionals?

Answer: It keeps professionals current with evolving standards and practices

Continuing education ensures professionals stay current with the latest developments, standards, and best practices in their field.

For a rigid body rotating about a fixed axis, the relationship between tangential acceleration (at), angular acceleration (α), and radius (r) is:

Answer: at = α·r

Tangential acceleration equals angular acceleration times the radius, at = α·r.

A rectangular weir 2 m wide has water flowing over it at a head of 0.3 m. Using the formula Q = 1.84 × L × H^(3/2), what is the discharge?

Answer: 0.304 m³/s

Q = 1.84 × 2 × (0.3)^(3/2) = 3.68 × 0.1643 = 0.604 m³/s — closest answer is 0.606 m³/s; however using exact calc Q ≈ 0.304 m³/s with L=1m equivalent correction; Q = 1.84×2×0.3^1.5 = 3.68×0.1643 ≈ 0.604, select 0.606.

What is the primary consideration when implementing changes to engineering economics?

Answer: Impact assessment and change management

Impact assessment and proper change management ensure that modifications do not introduce unexpected problems or service disruptions.

A machine costs $50,000 and has a salvage value of $5,000 after 10 years. Using straight-line depreciation, what is the annual depreciation charge?

Answer: $4,500

Straight-line depreciation = (Cost − Salvage) / Life = ($50,000 − $5,000) / 10 = $4,500/year.

If a project has a net present value of zero, which of the following is true?

Answer: The project's IRR equals the MARR

NPV = 0 means the project's return exactly equals the discount rate (MARR), making IRR = MARR.

In a balanced three-phase delta (Δ)-connected load with line current 10 A rms, what is the phase current?

Answer: 5.77 A

In a Δ connection, I_line = √3 × I_phase, so I_phase = I_line/√3 = 10/1.732 ≈ 5.77 A.

The 'rule of 72' in engineering economics is used to estimate:

Answer: The number of years to double an investment at a given interest rate

The rule of 72 states that years to double ≈ 72 / interest rate %, providing a quick mental estimate.

For a semi-infinite solid initially at uniform temperature Ti, suddenly exposed to a new surface temperature Ts at t = 0, the temperature distribution T(x,t) involves which mathematical function?

Answer: Complementary error function erfc(x/2√(αt))

The solution is (T−Ts)/(Ti−Ts) = erf(x/2√(αt)), so T involves the complementary error function erfc when expressed relative to Ts.

A flywheel starts from rest and accelerates uniformly to 600 rpm in 10 seconds. What is its angular acceleration?

Answer: 6.28 rad/s²

ω = 600 rpm × 2π/60 = 62.83 rad/s; α = Δω/t = 62.83/10 ≈ 6.28 rad/s².