Applied Technology: From Requirement to Validated Choice
The Applied Technology domain tests how you turn a stated need into a working, safe, and economical technical solution. Questions ask you to interpret specifications, compare options, apply physical relationships, and explain why a design would fail in service. You must reason with units, ratings, tolerances, and constraints rather than recall product names.
Core rules and concepts
- Start with function: state what must be achieved, then list constraints such as power, mass, cost, environment, lifetime, and applicable standards.
- Quantify before choosing. Convert inputs to consistent SI units and keep energy (J, kWh) distinct from power (W, kW).
- Use continuous or nameplate ratings for steady duty; check peak, stall, and starting conditions separately.
- Design for the weakest link: fasteners, seals, connections, and control limits can set the real system rating.
- Treat tolerance as a permitted range, not a target. Stack tolerances worst-case unless statistical assembly is justified.
- Apply a safety factor where loads are uncertain, dynamic, fatigue-prone, or human-facing.
- Validate against the actual requirement, not a convenient proxy.
Worked example
A 12 V gear motor draws 2.5 A while lifting a 3.0 kg load 0.80 m in 4.0 s. Input power is P_in = VI = 12 × 2.5 = 30 W. Useful output power is P_out = mgh/t = (3.0 × 9.81 × 0.80) / 4.0 = 5.9 W. Efficiency is 5.9 / 30 = 0.196, about 20%. The other 24 W is lost mainly as heat in the motor and gearbox. Therefore the supply and enclosure must handle the input power and dissipate heat; describing the motor as a 30 W output device would be wrong.
Traps that cost marks
- Mixing W and Wh, or using minutes where seconds are required.
- Using stall torque as running torque.
- Ignoring efficiency and then undersizing the supply.
- Assuming a nominal dimension is the worst-case dimension.
- Treating safety and EMC requirements as paperwork rather than design inputs.