That's Not a Letter Trivia Quiz

Answer: acceleration

The acceleration of an object is the rate of change of an object's velocity. In turn, an object's velocity is the rate of change of its position. Therefore, acceleration can be thought of as the rate of change of an object's rate of change. In calculus and physics, acceleration is defined as the second derivative of an object's position function: a(t) = d^2/dt^2 [s(t)].

The value of an object's acceleration can be positive or negative, and it is a pet peeve of many physicists when negative acceleration is described as "deceleration."

A can also refer to the a side of a triangle, a measurement of a conic curve, the area of a shape, or the apothem of a regular polygon.

Answer: y-intercept

The number b corresponds to the y-intercept of a line (the place at which the line crosses the y-axis). This point always occurs when x = 0, making the y-intercept of a non-vertical line (0,b).

A, b, and c are frequently used to represent the sides of a triangle, or parts of a conic curve. B is also used to represent the base of some geometric shapes, such as triangles and trapezoids.

Answer: 299,792,458 meters per second

The speed of light in a vacuum is a universal constant, and defined as being exactly equal to 299,792,458 meters per second. It is the maximum speed at which anything can travel through the universe. It relates matter and energy, as well as space and time.

C is a superstar among math and the sciences. In addition to being the speed of light, it can also be a side in a triangle (and is always the hypotenuse of a right triangle), describes parts of conic curves, and can be the circumference of a circle, an abbreviation for Coulomb in electromagnetism, a denotation of combinations in statistics, the constant in integral calculus, and the set of all complex numbers (in blackboard bold font).

Answer: diameter

Circles have three important measurements: circumference, diameter, and radius. The circumference is the distance around the whole circle, the radius is the distance from the center to the edge of a circle, and the diameter is the distance between opposite points on the edge of a circle. The diameter of a circle is always twice its radius (d = 2r), while the circumference and diameter are related by the special number, pi (C = pi*d).

D is also the number that describes the diagonal of a quadrilateral in geometry, the density of a substance in science, or the distance involved in a calculation in general.

Answer: 2.718281

The number e is defined as the limit of (1 + 1/n)^n as n increases without bound. Conceptually, it represents the limit of any growth or decline rate that is dependent on itself and not restricted by limiting factors. Situations involving exponential growth include continuous interest rates and the populations of small organisms, like bacteria. Exponential decay is applicable to situations such as nuclear half-lives or cooling rates. Students of Calculus II and Differential Equations study these growth/decline rates in detail.

E is commonly used in the sciences to represent energy, such as in Einstein's mass-energy equivalence, E = mc^2. E is also used to represent error in statistics, and the eccentricity of a conic curve.

Answer: False

Factorial is an operation, not a number, and it is represented by an exclamation mark. For example, 6! = 6 factorial = 6*5*4*3*2*1 = 720. The letter F is used in part to represent the Hypergeometric Function, a statistical distribution that involves factorials, but is not a number in either instance regardless.

The letter f is frequently used in mathematics to denote a function in general, such as f(x) (read "f of x"). F is a notable number in physics, where it represents the force of an object in mechanics (F = ma), and is an abbreviation for farad in electromagnetism. It also plays a role in statistics, where F-scores are used to to do hypothesis tests comparing the variances of two groups.

Answer: gravitational acceleration

The constant g is the gravitational acceleration exerted by planet Earth on all objects around it. As for all other objects in the universe, the gravitational acceleration constant is proportional to the Earth's mass. Unlike most other constants, this one is not universal and actually varies slightly from place to place even on Earth, due to the slightly uneven surface of the planet.

When capitalized, G becomes the universal gravitational constant, equal to 6.674*10^-11 meters-cubed per kilogram per second per second. In measurements, g is an abbreviation for gram, a metric unit of mass.

Answer: Max Planck

Max Planck originally introduced the constant h as a way of making his experimental measurements work. It turned out to be a genuine discovery with revolutionary implications: energy can be broken down into small but finite quantities, similar to the way that matter can. This discovery is of great importance to quantum mechanics.

The Planck constant is equal to 6.626*10^-34 joule seconds. It is an important part of energy equations that involve the frequency or wavelength of light. The h-with-a-small-dash version is the same constant but divided by 2 pi, and is involved with angular momentum. It is known as the reduced Planck constant.

Science also uses H as a stand-in for enthalpy, and the intensity of a magnetic field. In mathematics, h can be the height of a shape, or the horizontal shift of a conic curve. H is also the abbreviation of henry, the SI unit of inductance.

Answer: imaginary unit

The number i is quite real, much to the consternation of the non-mathematically inclined. It is technically defined as 'a number that is a solution to the equation i^2 = -1'; it follows that there are a pair of numbers that satisfy this equation.

Imaginary numbers allow the expression of equivalences in mathematics that could otherwise not be noted. The best-known of these is Euler's formula -- e^(ix) = cos(x) + i*sin(x) -- which relates exponential and sinusoidal expressions via the use of imaginary numbers. Graphs involving changing imaginary numbers are difficult to imagine, but are often visually represented by color gradients on a coordinate system.

In physics, I is the current through a conductor (such as in Ohm's Law, V = IR) or the moment of inertia of an object. In finance, i is the interest rate in the growth of money.

Answer: vector

Vectors are a major component of any physics course, and they are examined in detail in higher-level calculus as well. A vector is a mathematical object that has both a magnitude and a direction, and can be broken down into individual components that traverse each of the three physical dimensions. The components in these three dimensions are represented by the letters i, j, and k.

J has few quantitative uses beyond vectors, though it is notably an abbreviation for joule, a measured unit defined in SI units as a kilogram meter-squared per second per second.

K is used to describe the parity of a number (with 2k being an even number, while 2k+1 is an odd number), and is also the vertical shift of a conic curve. K is also an abbreviation for kilo (and thus, 1000) and Kelvin, the SI unit of temperature. In the sciences, k is often used to represent the idea of 'some constant', such as F = kx in Hooke's Law.

Answer: liter

The liter is a metric unit of volume equal to 1,000 cubic centimeters. The SI unit of volume is the cubic meter, equivalent to 1,000 liters, but the liter and its subdivision the milliliter are more common in science.

Owing to its similarity to the number 1, L is always altered when used as a number. The abbreviation for liter is a capital L, the length of an object is represented with a lowercase but curled l, and the Laplace transformation is written with an uppercase, fancy L (similar in appearance to the symbol for the British pound).

Answer: momentum

It's little wonder M is popular in the sciences: it commonly stands for mass, as in Newton's Law (F = ma), or or as the molar mass of chemical compounds. Chemists use it frequently in stoichiometry, where calculations commonly involve molarity and molality.

This in turn is why p is used for momentum rather than m. Momentum is related to mass and velocity by the equation p = mv; you can see how it may create issues if m was used for momentum as well.

M is the abbreviation for meter, the SI unit of length. M is also used in algebra as the slope of a general line, y = mx + b.

Answer: number of items

As opposed to numbers in general, n is normally used to represent the number of items involved in a calculation. Most such quantities are natural numbers (whole and positive). The number of sides of a shape, number of moles of an ideal gas, number of loan payments, and number of items in a population are all represented with the letter n.

If capitalized, the letter N is the abbreviation for Newton, the SI unit of force. And naturally, a blackboard bold N represents the set of natural numbers.

Answer: none of these

O is the only English letter not used to describe numeric quantities. The reason should be obvious: it looks far too similar to the number 0 for such a task.

Odd numbers in general are represented with the expression 2k+1, while percentages use the % sign. The empty set uses what appears to be an O, but with a slash mark through it. This symbol is actually based on a Danish/Norwegian letter, one which is distinct from the actual letter O.

O does see notational use as a function. Big O notation refers to the limit behavior of a function, as that function approaches a given value. This is of particular note in computer science, where blocks of code can be classified by the efficiency of their algorithms.

Answer: interest

Interest equations depend on the principal (P), interest rate (i or r), time (t), and compounding number (n) to determine the present or future value of money. Compound interest is calculated with the equation P = P0*(1+r)^t or the variant P = P0*(1+i/n)^(nt). Finance in general relies heavily on these variables, and the financial growth or decline of money involving compound interest is exponential in nature.

Among its other uses, p represents proportions in statistics, the perimeter of most shapes, pressure in chemistry and physics, and momentum in physics. P is also used as a denotation symbol in statistics for probability and permutations.

Answer: set of rational numbers

Set theory is a generalization of sets of numbers and their properties. Certain sets of numbers are of particular interest to mathematicians: complex (C), real (R), rational (Q), integers (Z), and natural (N). The thick font type used for these sets is called blackboard bold.

The set of rational numbers is the set of all numbers that can be written as a "q"uotient of integers. There are more rational numbers than there are integers, but fewer rational numbers than real or complex numbers.

Chemistry uses q to represent an item's heat capacity, which is a product of its mass, specific heat, and temperature. Q is also seen in advanced mathematics as a stand-in for quaternions.

Answer: ideal gas laws

Ideal gases are a notable part of chemistry, and their major properties are related to each other by equation PV = nRT. The P stands for pressure (atmospheres), V is volume (liters), n is number of moles, and T is temperature (kelvins). R is the constant value that obtained by taking the ratio of the pressure and volume to that of the number of moles and temperature.

Like any other constant that depends on units, R can be converted. For example, R is also equal to 62.36367 liter millimeters-of-mercury per kelvin per mole. However, it is usually easier to convert the other variables into liters, atmospheres, moles, and kelvins than to try and convert R for each parameter that is not one of those four units.

R is also of great interest to mathematicians, who use it to represent the radius of a circle, the interest rate of financial calculations, the correlation coefficient of a linear regression, and the set of all real numbers (when written in blackboard bold).

Answer: integral

What we now think of as "s" was once only used at the end of a word; in other places a longer, thinner version of the same letter was used. The integral symbol was adapted from this long s.

Conceptually, an integral is the accumulation of a quantity of infinitesimal changes. Visually, an integral represents the area between a curve and the x-axis. This concept of accumulation of change allows the calculation or numeric approximation of any quantities, even those with varying parameters. Some of the most important include arc lengths, areas, and volumes of any shapes, even those involving curves. Physics makes great use of integrals in instances where quantities like work, force, or mass are variable.

S is also notably used as the standard deviation of a sample in statistics, the side length of a square in geometry, the position function of an object in math and physics, and the spin value of an electron in quantum chemistry.

Answer: True

Time is a very important variable, and quantities of time are appropriately represented with the letter t. The equations s = s0 + v0*t + 0.5*g*t^2, v = v0 + g*t, and a = g are the position, velocity, and acceleration equations of an object that is thrown away from the center of the Earth. Here, g represents the gravitational constant, while s0 and v0 are the object's initial position and initial velocity.

T is also the abbreviation for tesla, the SI unit of magnetic field strength. T is the independent variable in parametric equations, where it also normally stands for time. Additionally, T is used to represent temperature, and t-scores are statistical values associated with t-distributions.

Answer: unit

The unit is a very important concept in mathematics, as it is the definition of the base item in any mathematical system being used. The unit for real numbers is 1, and for imaginary numbers is i.

In vector systems, the unit vector of a given vector is defined as u = v/|v|. Dividing a vector by its magnitude standardizes its size to 1 without altering its direction.

Measured properties also have units (such as pounds, liters, or kelvins), but such units have their own individual descriptions and u is not used to describe any of them.

U is also used to shift certain expressions in what is known as a u-substitution. For example, if I had the expression (x + 1)*(x - 7)^0.5, I may want to substitute u = x - 7 into the expression. The shifted expression would become u^1.5 + 8u^0.5; this type of substitution is a necessary step in solving certain types of integrals and partial fraction decompositions.

Answer: 3

Volume is a three-dimensional quantity dependent on an object's length, width, and height. Volume is a commonly measured scientific quantity, and is often encountered while studying the geometry of three-dimensional objects. Shapes with varying sides require calculus to determine their volumes.

V is also encountered in the sciences as an object's velocity or the voltage between two points, and is used to represent vectors in general.

Answer: work

Physics defines work as the product of a constant force and the displacement it causes. The work done by a varying force can similarly be measured, but the product Fd would have to be taken as an integral over the displacement. The SI unit of work is the joule.

The number w can also be the width of a shape, mainly in geometry. W is also the abbreviation for watt, the SI unit of power.

Answer: as a general unknown variable

As introduced in algebra, x is almost always "that number that you have to solve for." When extending the algebraic system into two and three dimensions, it takes the role of the independent variable, which can take on whatever value it pleases and controls the change in any dependent variables in an equation.

This general duty of x is so important that it has few additional uses. It is used in Hooke's Law (F = kx) to represent the distance a spring is stretched. X is also used with y and z in mathematics to represent general points in the Cartesian coordinate system.

Answer: dependent variable

When setting up functions, y is normally used to indicate the dependent variable: the one whose values depend on another, independent variable, usually x.

Due to its general purpose as a dependent variable, y has few other roles in describing quantitative variables. It (along with x and z) is used to describe the axes as well as general points in the Cartesian coordinate system.

Answer: statistics

A z-score is a score that is standardized to the normal distribution (bell curve) by subtracting the data's mean and then dividing by the standard deviation of the data: in other words, z = (x-bar - mu)/sigma. Z-scores are indicative of the percentile of a value and where it is relative to the rest of its population.

Along with x and y, z can be used to describe the axes and general points of the Cartesian coordinate system, with z representing the extension of the system to three dimensions. A blackboard bold Z is also used to represent the set of all integer numbers.