PAF Aeronautical Engineering Initial Test flashcards

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

Present perfect with since

Since marks a starting point in time, and the present perfect (has or have plus past participle) links that past point to the present situation.

Between versus among

Between is used for two people or things and takes an object pronoun such as me; among is used for three or more.

Passive voice formation

The object becomes the subject, the verb becomes a form of be plus the past participle, and the doer is introduced with by.

Semicolon use

A semicolon joins two independent clauses that are closely related in meaning and are not already linked by a conjunction.

Dangling modifier

An introductory phrase must describe the subject that immediately follows the comma; if it describes something else, the modifier is said to dangle.

Active versus passive voice

In the active voice the subject performs the action; in the passive voice the subject receives the action performed by someone or something else.

Percentage change formula

Percentage change equals the change divided by the original value, multiplied by one hundred; a negative result indicates a decrease rather than an increase.

Quadratic formula

For ax squared plus bx plus c equals zero, x equals negative b plus or minus the square root of b squared minus 4ac, all divided by 2a.

LCM and HCF product rule

For any two positive integers, the product of their lowest common multiple and highest common factor equals the product of the numbers themselves.

Average speed, equal distances

When equal distances are covered at speeds x and y, the average speed is 2xy divided by x plus y, not the arithmetic mean.

Area of a trapezium

The area of a trapezium equals half the sum of the two parallel sides multiplied by the perpendicular height between those parallel sides.

Simple interest formula

Simple interest equals principal multiplied by rate multiplied by time, divided by one hundred, where the rate is a percentage per year.

Sum of first n numbers

The sum of the first n natural numbers is n multiplied by n plus one, divided by two, which quickly adds consecutive integers.

Equations of motion

For constant acceleration: v equals u plus at, s equals ut plus half at squared, and v squared equals u squared plus 2as.

Newton's second law

The net force acting on a body equals its mass multiplied by its acceleration, so the same force accelerates a smaller mass more.

Kinetic and potential energy

Kinetic energy of a moving body is half mv squared; gravitational potential energy of a raised body is mgh, where h is height.

Ohm's law

At constant temperature, the current through a conductor is directly proportional to the potential difference across it, giving V equals IR.

Resistors in parallel

For resistors connected in parallel, the reciprocal of the total resistance equals the sum of the reciprocals of the individual resistances.

Wave equation

Wave speed equals frequency multiplied by wavelength; frequency is measured in hertz and wavelength in metres for the speed in metres per second.

Mirror formula

One divided by focal length equals one divided by image distance plus one divided by object distance, applied with a consistent sign convention.

Opposite letter pairs

Letters whose alphabet positions add up to twenty-seven are opposite pairs, so A pairs with Z, B with Y, and C with X.

Analogy relationship types

Common relationships tested are worker and tool, cause and effect, part and whole, and synonym; name the exact link before choosing an option.

Syllogism basic rule

From the statement that all A are B, you cannot validly conclude that all B are A; conclusions must follow from every statement given.

Right and left turns

Facing north, a right turn points you east and a left turn points you west; each such turn covers ninety degrees.

Blood relation notation

Draw a family tree with generations on separate rows and mark males and females explicitly rather than assuming gender from a name.

Number series strategy

Check differences first, then ratios, then perfect squares and cubes, and finally two interleaved series at odd and even positions.

Mirror image rule

A mirror placed vertically at the side reverses left and right while keeping top and bottom unchanged; a horizontal mirror does the reverse.

Water image

In a water reflection the top and the bottom of the figure interchange, while the left and right sides stay exactly as they were.

Paper folding hole count

Unfold the paper in the reverse order of folding, remembering that each fold doubles the number of holes made by a single punch.

Painted cube corners

A cube painted on all faces and cut into n cubed small cubes always has eight corner cubes with exactly three painted faces.

One-face painted cubes

When a painted cube is cut into n cubed small cubes, those with exactly one painted face number six times n minus two squared.

Rotation by 90 degrees

A clockwise quarter turn moves the top side of a figure to the right side, while an anticlockwise quarter turn moves it to the left.