Science
Coverage
Basic physics (units, motion, force, work and energy, heat, light, sound, electricity), chemistry (matter, atom, acids and bases, water, common salts), biology (cell, human systems, nutrition, vitamins, blood groups, communicable disease), plus applied science used in policing: fingerprints, DNA, toxicology and basic cyber hygiene.
Anchors
- SI base units: metre, kilogram, second, ampere, kelvin, mole, candela; force in newtons, pressure in pascals, power in watts.
- Newton's laws; F = ma; work = force × displacement; power = work ÷ time.
- Blood: O negative is the universal red-cell donor; AB positive the universal recipient.
- Vitamins: A vision, B-complex energy metabolism, C collagen and scurvy, D calcium absorption, K clotting.
- Acids have pH below 7, bases above 7; pH 7 is neutral at 25 °C.
Worked example
A 1,000 kg vehicle accelerates uniformly from rest to 20 m/s in 5 s. Find the force. Acceleration a = (20 − 0)/5 = 4 m/s². F = ma = 1,000 × 4 = 4,000 N. Distance covered is s = ½at² = ½ × 4 × 25 = 50 m - often the second part of the same question.
Traps
- Confusing mass and weight (weight = mg; 60 kg weighs about 588 N at g = 9.8).
- Reading displacement as distance when direction reverses.
- Mixing the red-cell universal donor with plasma compatibility, which runs the opposite way.
- Calling dissolving sugar a chemical change; it is physical.