Angola Naval Academy Entrance Exam flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Quadratic formula

For ax² + bx + c = 0 with a ≠ 0, the solutions are x = (-b ± √(b² - 4ac)) / 2a. The discriminant b² - 4ac determines how many real roots exist.

Pythagorean theorem

In a right triangle, the square of the hypotenuse equals the sum of the squares of the two legs: a² + b² = c². It applies only to right triangles.

Arithmetic progression sum

For an arithmetic sequence with first term a₁ and common difference d, the nth term is a₁ + (n-1)d and the sum of n terms is n(a₁ + aₙ)/2.

Probability complement rule

The probability that an event does not occur equals 1 minus the probability that it occurs: P(not A) = 1 - P(A). Probabilities always lie between 0 and 1.

Proparoxítona accent rule

In Portuguese, every proparoxítona word - one stressed on the antepenultimate syllable, such as 'lâmpada' or 'médico' - is always written with an accent.

Crase usage

Crase (à) marks the contraction of preposition 'a' with article 'a' before feminine nouns, as in 'vou à escola'. It is not used before masculine nouns or most verbs.

Os Lusíadas

Epic poem by Luís de Camões, published in 1572, in ten cantos. It celebrates Vasco da Gama's sea route to India and is Portugal's national epic.

Fernando Pessoa heteronyms

Distinct authorial personas created by Fernando Pessoa, chiefly Alberto Caeiro, Ricardo Reis and Álvaro de Campos. Each has its own style, biography and worldview, separate from the orthonym Pessoa.

Newton's second law

The net force acting on a body equals its mass times its acceleration: F = m·a. Force is measured in newtons, mass in kilograms, acceleration in m/s².

Ohm's law

For a conductor at constant temperature, voltage equals current times resistance: V = I·R. Voltage is in volts, current in amperes, resistance in ohms.

Kinetic energy

The energy a body possesses due to its motion, given by Eₖ = ½mv², where m is mass and v is speed. Doubling speed quadruples kinetic energy.

Wave equation

For any periodic wave, speed equals frequency times wavelength: v = f·λ. Frequency is in hertz and wavelength in metres.

Mole and Avogadro's number

One mole of any substance contains 6.022 × 10²³ elementary particles and has a mass in grams numerically equal to its molar mass.

pH scale

pH = -log[H⁺]. At 25 °C a solution with pH below 7 is acidic, pH equal to 7 is neutral, and pH above 7 is basic.

Ionic versus covalent bonds

Ionic bonds form by transfer of electrons, typically between a metal and a non-metal. Covalent bonds form by sharing electron pairs, typically between non-metals.

Oxidation and reduction

Oxidation is loss of electrons and an increase in oxidation number. Reduction is gain of electrons and a decrease in oxidation number; both occur together in redox reactions.

Photosynthesis equation

Green plants convert carbon dioxide and water into glucose and oxygen using light energy: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. It occurs in chloroplasts.

Prokaryotic versus eukaryotic cells

Prokaryotic cells have no membrane-bound nucleus or organelles and include bacteria. Eukaryotic cells have a true nucleus and membrane-bound organelles and include plants and animals.

DNA base pairing

In DNA, adenine pairs with thymine and guanine with cytosine. In RNA, uracil replaces thymine. The molecule is a double helix of nucleotides.

Mendel's law of segregation

Each organism carries two alleles for each gene; during gamete formation they separate so each gamete receives only one allele, randomly chosen.

Angolan independence date

Angola became independent from Portugal on 11 November 1975. Agostinho Neto proclaimed the People's Republic of Angola and became its first President.

Berlin Conference

A meeting of European powers held in 1884-1885 that set rules for the colonisation and partition of Africa, including free navigation and effective occupation principles.

Angola's borders

Angola borders the Democratic Republic of the Congo to the north and northeast, Zambia to the east, Namibia to the south, and the Atlantic Ocean to the west.

Lines of latitude

Imaginary horizontal circles: the Equator at 0°, the Tropics of Cancer and Capricorn at 23.5° north and south, and the polar circles at 66.5° north and south.

Angolan Constitution supremacy

The Constitution of the Republic of Angola, adopted in 2010, is the supreme law. Any law or act contrary to its provisions is invalid.

Chain of command

The military principle by which orders pass downward from superior to subordinate through each rank level, while accountability and responsibility flow upward.

Military discipline

Strict obedience to lawful orders, punctuality, correct wearing of uniform and respect for superiors. It sustains unit cohesion and operational effectiveness.

Duties of the armed forces

Angola's armed forces defend national sovereignty, territorial integrity and the constitutional order, and may support civil protection and humanitarian tasks.

Present perfect tense

Formed with have or has plus the past participle, as in 'she has finished'. It links a past action to the present or refers to time not specified.

Passive voice formation

The passive is formed with the correct tense of 'be' plus the past participle, as in 'the order was given'. The original object becomes the subject.

Third conditional

Used for unreal past situations: if + past perfect, then would have + past participle, as in 'If he had studied, he would have passed'.

Prepositions of time

Use 'in' with months, years and seasons; 'on' with days and dates; 'at' with clock times and fixed expressions such as 'at night'.