PiCAT flashcards

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

Photosynthesis equation

Plants use light energy to convert carbon dioxide and water into glucose and oxygen: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.

pH scale

A measure of acidity ranging from 0 to 14: values below 7 are acidic, 7 is neutral, and values above 7 are basic or alkaline.

Weight versus mass

Mass is the amount of matter in an object and stays constant; weight is the gravitational force on that mass and changes with gravity.

Arithmetic mean

Add all the values in a data set, then divide the total by how many values there are; the result is the average, or arithmetic mean.

Percent change formula

Percent change equals the new value minus the old value, divided by the old value, then multiplied by 100 to make it a percent.

Distance-rate-time relationship

Distance traveled equals rate (speed) multiplied by time: d = rt. Rearranged, rate = d ÷ t and time = d ÷ r.

Combined work rate

When two workers or machines work together, add their individual rates in jobs per hour, then divide one job by that combined rate.

Root 'spect'

The Latin root spect means to look or see, as in inspect (look into), spectator (one who watches), and perspective (a way of seeing).

Prefix 'bene-'

The prefix bene- means good or well, as in beneficial (producing good), benevolent (wishing good), and benediction (a spoken blessing).

Contrast context clues

Words such as but, although, and however signal a contrast, so an unfamiliar word near them often means the opposite of nearby wording.

Main idea

The central point the author develops throughout a passage; it is broader than any single detail and often stated in the first or last sentence.

Valid inference

A conclusion logically supported by the passage's details but not stated directly; it must not contradict the text or rely on outside assumptions.

Author's purpose

The reason a passage was written, commonly to inform, persuade, entertain, or describe, which shapes the tone and the details chosen.

Pythagorean theorem

In a right triangle, the square of the hypotenuse equals the sum of the squares of the other two sides: a² + b² = c².

Slope formula

The slope of a line through two points is the change in y divided by the change in x: m = (y₂ − y₁) ÷ (x₂ − x₁).

Area of a circle

The area enclosed by a circle equals pi times the radius squared: A = πr². Its circumference is 2πr.

Zero and negative exponents

Any nonzero number raised to the zero power equals 1; a negative exponent gives the reciprocal, so x⁻ⁿ equals 1 ÷ xⁿ.

Ohm's law

Voltage equals current multiplied by resistance: V = IR. If any two of the three values are known, the third can be calculated.

Electrical power formulas

Power in watts equals voltage times current (P = VI); it also equals current squared times resistance (P = I²R).

Parallel circuit resistance

In a parallel circuit the voltage across each branch is equal, and total resistance follows 1/R = 1/R₁ + 1/R₂ and so on.

Diode function

A diode conducts current in only one direction, acting as a one-way valve; an LED is a diode that emits light when forward-biased.

Four-stroke engine cycle

A gasoline engine repeats intake, compression, power, and exhaust strokes; the spark plug fires near the end of compression to start the power stroke.

Alternator purpose

Driven by an engine belt, the alternator generates electricity to recharge the battery and run the vehicle's electrical system while the engine operates.

Engine cooling system

Coolant circulates through the engine and radiator; the thermostat opens at a set temperature to control flow and hold the engine at operating temperature.

Saw teeth per inch

Blades with fewer teeth per inch cut faster and rougher, while blades with more teeth per inch cut slower and leave a smoother finish.

Pilot hole purpose

A small hole drilled before driving a screw or nail; it prevents wood from splitting, guides the fastener, and eases driving near edges.

Sandpaper grit number

Lower grit numbers are coarser and remove material quickly, while higher grit numbers are finer and produce a smooth finish for final sanding.

Lever mechanical advantage

For a lever, mechanical advantage equals effort arm length divided by resistance arm length; a longer effort arm multiplies the applied force.

Movable pulley advantage

A single movable pulley supports the load with two rope segments, giving a mechanical advantage of 2 so half the force lifts the load.

Hydraulic pressure principle

Pressure applied to a confined fluid is transmitted equally in all directions; force equals pressure times area, so a larger piston lifts more.

Mental rotation strategy

Mentally turn the piece in the same direction as the answer choices; rotations keep the part's shape, while mirrored versions are always wrong.

Matching tabs and slots

Locate unique tabs, notches, and slots on each piece and confirm the assembled figure has a matching receiver in the correct position.