Engineering and Technology Content Knowledge and Skills
This domain tests the science, mathematics, and technical content a teacher must apply in lab settings: measurement, mechanics, energy, electricity, materials, fluid power, and graphic communication of designs. Problems are usually short quantitative calculations embedded in a practical scenario.
Measurement and units
- SI base units: meter, kilogram, second, ampere, kelvin, mole, candela; derived units include the newton, joule, watt, pascal, and ohm.
- Accuracy is closeness to the true value; precision is repeatability. A caliper reading 12.04 mm repeatedly against a true 12.00 mm is precise but not accurate.
- Significant figures follow measurement precision; convert by dimensional analysis so units cancel.
Mechanics and machines
- Equilibrium: ΣF = 0 and ΣM = 0; torque = force × perpendicular distance.
- Lever classes (fulcrum between load and effort; load between; effort between) and pulley systems trade force for distance, never energy.
- IMA comes from geometry (supporting rope segments, gear-tooth ratio, wheel radii); AMA is measured load ÷ effort. Efficiency = AMA ÷ IMA × 100%.
- Work = force × distance; power = work ÷ time; efficiency compares useful output to total input.
Electricity and materials
- Ohm's law V = IR; P = VI. Series resistances add; parallel resistances add reciprocally (1/RT = 1/R1 + 1/R2).
- Stress = force ÷ area; strain = change in length ÷ original length; Young's modulus is the slope of the elastic region. Yielding ends elastic behavior; fatigue is failure under repeated loading below yield.
Fluid power and graphics
Pascal's law: pressure transmits undiminished, so F1/A1 = F2/A2. Multiview (orthographic) drawings show front, top, and right side with hidden lines dashed; isometric shows three axes; dimensioning follows ASME Y14.5 conventions and tolerances define allowable variation.
Worked example
A pulley system with four supporting rope segments lifts a 200 N load with 60 N of effort. IMA = 4; AMA = 200 ÷ 60 = 3.33; efficiency = 3.33 ÷ 4 = 83%. Geometry sets the ideal, measurement sets the actual, and friction explains the gap.
Traps that cost marks
Swapping IMA and AMA; reporting efficiency above 100%; using the wrong distance for torque; adding parallel resistors directly; and confusing accuracy with precision.