Last-Week Handbook, Units, and Calculator Drills

Do not rebuild the course in the last week

The final week is for execution, not a new semester of theory. The highest return comes from faster Handbook navigation, cleaner unit handling, approved-calculator fluency, and short mixed sets that expose recurring traps. If you find a real gap, patch the standard FE version of it rather than chasing every derivation. Use a daily rhythm: 20–30 minutes of Handbook lookup, 20–30 minutes of unit and calculator drills, one timed mixed set, and immediate review. Keep notes as actions: not 'fluids bad' but 'pump input power = rhogQ*H divided by efficiency.'

Worked problem: USCS mass-versus-weight

A dynamics item gives a weight W = 96.6 lbf and acceleration a = 10 ft/s^2 and asks for the net force. In USCS, F = ma requires mass in slugs, where m = W/g = 96.6 / 32.2 = 3.00 slugs. Then F = 3.00 * 10 = 30.0 lbf. The most common FE error is plugging 96.6 lbm straight into F = ma, which mixes the pound-mass and pound-force systems and inflates the answer by the factor 32.2. Whenever a USCS dynamics problem appears, your first move is W/g to get slugs.

Worked problem: rpm and pressure basis

A shaft delivers P = 5 hp at N = 1750 rpm; find torque. Convert power: 5 hp × 550 ft·lbf/s = 2750 ft·lbf/s. Convert speed: omega = 2pi1750/60 = 183.3 rad/s. Torque T = P/omega = 2750 / 183.3 = 15.0 ft·lbf. Two conversions (hp→ft·lbf/s and rpm→rad/s) are both required; skipping either is a classic miss.

Pressure basis matters too. A gas-law or steam-table problem stating 80 psig must become absolute first: P_abs = 80 + 14.7 = 94.7 psia. Substituting 80 psig directly into PV = mRT understates pressure by 15% and is a deliberate distractor.

Unit and calculator discipline

FE Mechanical mixes SI and USCS, and the unit traps are predictable. In SI, kg is mass and weight is mg in newtons. In USCS, lbf is force, lbm is mass, and slugs appear in F = ma with ft/s^2. Use absolute pressure for gas laws and tables, and absolute temperature (K or R) for gas-law and radiation T^4 terms; temperature differences may stay in °C or K. Write units through every intermediate step in the last week — the habit catches wrong choices that differ by 32.2, 60, 144, 550, or 1000.

For the calculator, use only the model you will bring (an NCEES-approved unit). Confirm degree versus radian angle mode before any trigonometry, rehearse scientific notation, parentheses, stored variables, equation solving, and matrix or statistics functions if your model supports them, and clear old settings that could contaminate a calculation. In the last two days, lower volume and raise precision: short mixed sets, review every miss, and a one-page personal trap sheet — gauge versus absolute, radius versus diameter, rpm conversion, efficiency direction, beam boundary conditions, stress versus strength.

The goal is fewer preventable errors, not a feeling of confidence.

The conversion cluster worth memorizing

A handful of conversion factors generate most FE unit traps, and the answer choices are often spaced exactly by these numbers so a conversion slip lands on a wrong option. Drill them until automatic.

Worked check: a fan uses 2.0 hp for 8 hours; find energy in kWh. 2.0 hp × 746 W/hp = 1492 W = 1.492 kW; over 8 h that is 1.492 × 8 = 11.9 kWh. A candidate who forgets the 746 factor and treats 2 'hp' as 2 kW gets 16 kWh — a clean distractor. Build a single index card of this table plus your personal misses; reviewing it the morning of the exam is far more valuable than opening a new topic. The aim of the last week is not more knowledge but fewer dropped points, and unit fluency is the highest-yield place to harvest them.