Mathematics and Physics
Core numeracy
Most marks in this domain come from fluent unit handling. Know the SI base units (metre, kilogram, second, ampere, kelvin, mole, candela) and the derived ones: newton (kg·m/s²), pascal (N/m²), joule (N·m), watt (J/s). Prefixes must be instant recall, from nano (10⁻⁹) up to mega (10⁶); 1 kPa = 1 000 Pa and 1 MPa = 1 000 kPa.
Mechanics and heat
Newton's three laws, moments (M = F × d, with equilibrium of moments about a point), centre of gravity, pressure in fluids (P = F/A and P = ρgh), density and specific gravity, work, power and efficiency, and the gas laws (Boyle, Charles, and the combined gas law). Temperature conversion: K = °C + 273.15.
The traps
Gauge versus absolute pressure; mass versus weight (W = mg, g = 9.81 m/s²); degrees versus radians; mixing up area and circumference; rounding too early in a multi-step calculation; and ratio questions such as "what happens if the diameter doubles?" - the area goes up fourfold, not twofold.
Worked example
A force of 500 N acts on a piston of area 0.005 m². Pressure P = F/A = 500 ÷ 0.005 = 100 000 Pa = 100 kPa. Rule of thumb: convert every quantity to base SI units before substituting, then carry the units through the arithmetic - a wrong unit always means a wrong answer.