MATSEC SEC Core Science cheat sheet
MATSEC SEC Core Science · Keep the key ideas within reach.
Core Science
SI base units: length metre (m), mass kilogram (kg), time second (s), electric current ampere (A), temperature kelvin (K), amount of substance mole (mol), luminous intensity candela (cd).
Speed = distance ÷ time; acceleration = change in velocity ÷ time; weight = mass × gravitational field strength (g ≈ 10 N/kg on Earth); density = mass ÷ volume.
Newton's three laws: an object stays at rest or in uniform motion unless a resultant force acts; F = m × a; every action has an equal and opposite reaction.
Energy is conserved, not created or destroyed: forms include kinetic (½mv²), gravitational potential (mgh), elastic, chemical, thermal, electrical, sound and nuclear; efficiency = useful output ÷ total input × 100%.
Electrical relations: current is the same in series, voltage splits; voltage is the same across parallel branches; V = I × R; power P = V × I; charge Q = I × t.
Chemical formulae and equations: reactants → products; balanced equations conserve atoms; relative formula mass sums atomic masses; one mole contains 6.02 × 10²³ particles.
Acids (pH below 7) release H⁺ ions; alkalis (pH above 7) release OH⁻ ions; acid + base → salt + water; acid + metal → salt + hydrogen; acid + carbonate → salt + water + carbon dioxide.
Cell biology: plant cells have cell wall, chloroplasts and a permanent vacuole; animal cells do not; both share nucleus, cytoplasm, cell membrane, mitochondria and ribosomes; photosynthesis: carbon dioxide + water → glucose + oxygen (needs light and chlorophyll).
Genetics and ecology: DNA carries genes; human body cells are diploid (46 chromosomes), gametes haploid (23); food chains transfer energy, roughly 10% passes to the next trophic level; producers are at the base.