# Glossary

- Page ID
- 29443

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

Words (or words that have the same definition) | The definition is case sensitive | (Optional) Image to display with the definition [Not displayed in Glossary, only in pop-up on pages] | (Optional) Caption for Image | (Optional) External or Internal Link | (Optional) Source for Definition |
---|---|---|---|---|---|

(Eg. "Genetic, Hereditary, DNA ...") | (Eg. "Relating to genes or heredity") | The infamous double helix | https://bio.libretexts.org/ | CC-BY-SA; Delmar Larsen |

Word(s) |
Definition |
Image | Caption | Link | Source |
---|---|---|---|---|---|

beat frequency | frequency of beats produced by sound waves that differ in frequency | OpenStax | |||

beats | constructive and destructive interference of two or more frequencies of sound | OpenStax | |||

bow wake | v-shaped disturbance created when the wave source moves faster than the wave propagation speed | OpenStax | |||

Doppler effect | alteration in the observed frequency of a sound due to motion of either the source or the observer | OpenStax | |||

Doppler shift | actual change in frequency due to relative motion of source and observer | OpenStax | |||

fundamental | the lowest-frequency resonance | OpenStax | |||

harmonics | the term used to refer collectively to the fundamental and its overtones | OpenStax | |||

hearing | perception of sound | OpenStax | |||

loudness | perception of sound intensity | OpenStax | |||

notes | basic unit of music with specific names, combined to generate tunes | OpenStax | |||

overtones | all resonant frequencies higher than the fundamental | OpenStax | |||

phon | numerical unit of loudness | OpenStax | |||

pitch | perception of the frequency of a sound | OpenStax | |||

shock wave | wave front that is produced when a sound source moves faster than the speed of sound | OpenStax | |||

sonic boom | loud noise that occurs as a shock wave as it sweeps along the ground | OpenStax | |||

sound | traveling pressure wave that may be periodic; the wave can be modeled as a pressure wave or as an oscillation of molecules | OpenStax | |||

sound intensity level | unitless quantity telling you the level of the sound relative to a fixed standard | OpenStax | |||

sound pressure level | ratio of the pressure amplitude to a reference pressure | OpenStax | |||

timbre | number and relative intensity of multiple sound frequencies | OpenStax | |||

transducer | device that converts energy of a signal into measurable energy form, for example, a microphone converts sound waves into an electrical signal | OpenStax | |||

antinode | location of maximum amplitude in standing waves | OpenStax | |||

constructive interference | when two waves arrive at the same point exactly in phase; that is, the crests of the two waves are precisely aligned, as are the troughs | OpenStax | |||

destructive interference | when two identical waves arrive at the same point exactly out of phase; that is, precisely aligned crest to trough | OpenStax | |||

fixed boundary condition | when the medium at a boundary is fixed in place so it cannot move | OpenStax | |||

free boundary condition | exists when the medium at the boundary is free to move | OpenStax | |||

fundamental frequency | lowest frequency that will produce a standing wave | OpenStax | |||

intensity (I) | power per unit area | OpenStax | |||

interference | overlap of two or more waves at the same point and time | OpenStax | |||

linear wave equation | equation describing waves that result from a linear restoring force of the medium; any function that is a solution to the wave equation describes a wave moving in the positive x-direction or the negative x-direction with a constant wave speed v | OpenStax | |||

longitudinal wave | wave in which the disturbance is parallel to the direction of propagation | OpenStax | |||

mechanical wave | wave that is governed by Newton’s laws and requires a medium | OpenStax | |||

node | point where the string does not move; more generally, nodes are where the wave disturbance is zero in a standing wave | OpenStax | |||

normal mode | possible standing wave pattern for a standing wave on a string | OpenStax | |||

overtone | frequency that produces standing waves and is higher than the fundamental frequency | OpenStax | |||

pulse | single disturbance that moves through a medium, transferring energy but not mass | OpenStax | |||

standing wave | wave that can bounce back and forth through a particular region, effectively becoming stationary | OpenStax | |||

superposition | phenomenon that occurs when two or more waves arrive at the same point | OpenStax | |||

transverse wave | wave in which the disturbance is perpendicular to the direction of propagation | OpenStax | |||

wave | disturbance that moves from its source and carries energy | OpenStax | |||

wave function | mathematical model of the position of particles of the medium | OpenStax | |||

wave number | \(\frac{2 \pi}{\lambda}\) | OpenStax | |||

wave speed | magnitude of the wave velocity | OpenStax | |||

wave velocity | velocity at which the disturbance moves; also called the propagation velocity | OpenStax | |||

wavelength | distance between adjacent identical parts of a wave | OpenStax | |||

amplitude (A) | maximum displacement from the equilibrium position of an object oscillating around the equilibrium position | OpenStax | |||

critically damped | condition in which the damping of an oscillator causes it to return as quickly as possible to its equilibrium position without oscillating back and forth about this position | OpenStax | |||

elastic potential energy | potential energy stored as a result of deformation of an elastic object, such as the stretching of a spring | OpenStax | |||

equilibrium position | position where the spring is neither stretched nor compressed | OpenStax | |||

force constant (k) | characteristic of a spring which is defined as the ratio of the force applied to the spring to the displacement caused by the force | OpenStax | |||

frequency (f) | number of events per unit of time | OpenStax | |||

natural angular frequency | angular frequency of a system oscillating in SHM | OpenStax | |||

oscillation | single fluctuation of a quantity, or repeated and regular fluctuations of a quantity, between two extreme values around an equilibrium or average value | OpenStax | |||

overdamped | condition in which damping of an oscillator causes it to return to equilibrium without oscillating; oscillator moves more slowly toward equilibrium than in the critically damped system | OpenStax | |||

period (T) | time taken to complete one oscillation | OpenStax | |||

periodic motion | motion that repeats itself at regular time intervals | OpenStax | |||

phase shift | angle, in radians, that is used in a cosine or sine function to shift the function left or right, used to match up the function with the initial conditions of data | OpenStax | |||

physical pendulum | any extended object that swings like a pendulum | OpenStax | |||

resonance | large amplitude oscillations in a system produced by a small amplitude driving force, which has a frequency equal to the natural frequency | OpenStax | |||

restoring force | force acting in opposition to the force caused by a deformation | OpenStax | |||

simple harmonic motion (SHM) | oscillatory motion in a system where the restoring force is proportional to the displacement, which acts in the direction opposite to the displacement | OpenStax | |||

simple harmonic oscillator | a device that oscillates in SHM where the restoring force is proportional to the displacement and acts in the direction opposite to the displacement | OpenStax | |||

simple pendulum | point mass, called a pendulum bob, attached to a near massless string | OpenStax | |||

stable equilibrium point | point where the net force on a system is zero, but a small displacement of the mass will cause a restoring force that points toward the equilibrium point | OpenStax | |||

torsional pendulum | any suspended object that oscillates by twisting its suspension | OpenStax | |||

underdamped | condition in which damping of an oscillator causes the amplitude of oscillations of a damped harmonic oscillator to decrease over time, eventually approaching zero | OpenStax | |||

absolute pressure | sum of gauge pressure and atmospheric pressure | OpenStax | |||

Achimedes' principle | buoyant force on an object equals the weight of the fluid it displaces | OpenStax | |||

Bernoulli's equation | equation resulting from applying conservation of energy to an incompressible frictionless fluid: $$p + \frac{1}{2} \rho v^{2} +\rho gh = constant,$$throughout the fluid | OpenStax | |||

Bernoulli's principle | Bernoulli's equation applied at constant depth:$$p_{1} + \frac{1}{2} \rho v_{1}^{2} = p_{2} + \frac{1}{2} \rho v_{2}^{2}$$ | OpenStax | |||

buoyant force | net upward force on any object in any fluid due to the pressure difference at different depths | OpenStax | |||

density | mass per unit volume of a substance or object | OpenStax | |||

flow rate | abbreviated Q, it is the volume V that flows past a particular point during a time t, or Q = \(\frac{dV}{dt}\) | OpenStax | |||

fluids | liquids and gases; a fluid is a state of matter that yields to shearing forces | OpenStax | |||

gauge pressure | pressure relative to atmospheric pressure | OpenStax | |||

hydraulic jack | simple machine that uses cylinders of different diameters to distribute force | OpenStax | |||

hydrostatic equilibrium | state at which water is not flowing, or is static | OpenStax | |||

ideal fluid | fluid with negligible viscosity | OpenStax | |||

laminar flow | type of fluid flow in which layers do not mix | OpenStax | |||

Pascal's principle | change in pressure applied to an enclosed fluid is transmitted undiminished to all portions of the fluid and to the walls of its container | OpenStax | |||

Poiseuille's law | rate of laminar flow of an incompressible fluid in a tube: $$Q = \frac{(p_{2} - p_{1}) \pi r^{4}}{8 \eta l} \ldotp$$ | OpenStax | |||

Poiseuille’s law for resistance | resistance to laminar flow of an incompressible fluid in a tube: $$R = \frac{8 \eta l}{\pi r^{4}}$$ | OpenStax | |||

pressure | force per unit area exerted perpendicular to the area over which the force acts | OpenStax | |||

Reynolds number | dimensionless parameter that can reveal whether a particular flow is laminar or turbulent | OpenStax | |||

specific gravity | ratio of the density of an object to a fluid (usually water) | OpenStax | |||

turbulence | fluid flow in which layers mix together via eddies and swirls | OpenStax | |||

turbulent flow | type of fluid flow in which layers mix together via eddies and swirls | OpenStax | |||

viscosity | measure of the internal friction in a fluid | OpenStax | |||

action-at-a-distance force | type of force exerted without physical contact | OpenStax | |||

aphelion | farthest point from the Sun of an orbiting body; the corresponding term for the Moon’s farthest point from Earth is the apogee | OpenStax | |||

apparent weight | reading of the weight of an object on a scale that does not account for acceleration | OpenStax | |||

black hole | mass that becomes so dense, that it collapses in on itself, creating a singularity at the center surround by an event horizon | OpenStax | |||

escape velocity | initial velocity an object needs to escape the gravitational pull of another; it is more accurately defined as the velocity of an object with zero total mechanical energy | OpenStax | |||

event horizon | location of the Schwarzschild radius and is the location near a black hole from within which no object, even light, can escape | OpenStax | |||

gravitational field | vector field that surrounds the mass creating the field; the field is represented by field lines, in which the direction of the field is tangent to the lines, and the magnitude (or field strength) is inversely proportional to the spacing of the lines; other masses respond to this field | OpenStax | |||

gravitationally bound | two object are gravitationally bound if their orbits are closed; gravitationally bound systems have a negative total mechanical energy | OpenStax | |||

Kepler’s first law | law stating that every planet moves along an ellipse, with the Sun located at a focus of the ellipse | OpenStax | |||

Kepler’s second law | law stating that a planet sweeps out equal areas in equal times, meaning it has a constant areal velocity | OpenStax | |||

Kepler’s third law | law stating that the square of the period is proportional to the cube of the semi-major axis of the orbit | OpenStax | |||

neap tide | low tide created when the Moon and the Sun form a right triangle with Earth | OpenStax | |||

neutron star | most compact object known—outside of a black hole itself | OpenStax | |||

Newton’s law of gravitation | every mass attracts every other mass with a force proportional to the product of their masses, inversely proportional to the square of the distance between them, and with direction along the line connecting the center of mass of each | OpenStax | |||

non-Euclidean geometry | geometry of curved space, describing the relationships among angles and lines on the surface of a sphere, hyperboloid, etc. | OpenStax | |||

orbital period | time required for a satellite to complete one orbit | OpenStax | |||

orbital speed | speed of a satellite in a circular orbit; it can be also be used for the instantaneous speed for noncircular orbits in which the speed is not constant | OpenStax | |||

perihelion | point of closest approach to the Sun of an orbiting body; the corresponding term for the Moon’s closest approach to Earth is the perigee | OpenStax | |||

principle of equivalence | part of the general theory of relativity, it states that there no difference between free fall and being weightless, or a uniform gravitational field and uniform acceleration | OpenStax | |||

Schwarzschild radius | critical radius (RS) such that if a mass were compressed to the extent that its radius becomes less than the Schwarzschild radius, then the mass will collapse to a singularity, and anything that passes inside that radius cannot escape | OpenStax | |||

space-time | concept of space-time is that time is essentially another coordinate that is treated the same way as any individual spatial coordinate; in the equations that represent both special and general relativity, time appears in the same context as do the spatial coordinates | OpenStax | |||

spring tide | high tide created when the Moon, the Sun, and Earth are along one line | OpenStax | |||

theory of general relativity | Einstein’s theory for gravitation and accelerated reference frames; in this theory, gravitation is the result of mass and energy distorting the space-time around it; it is also often referred to as Einstein’s theory of gravity | OpenStax | |||

tidal force | difference between the gravitational force at the center of a body and that at any other location on the body; the tidal force stretches the body | OpenStax | |||

universal gravitational constant | constant representing the strength of the gravitational force, that is believed to be the same throughout the universe | OpenStax | |||

breaking stress (ultimate stress) | value of stress at the fracture point | OpenStax | |||

bulk modulus | elastic modulus for the bulk stress | OpenStax | |||

bulk strain (or volume strain) | strain under the bulk stress, given as fractional change in volume | OpenStax | |||

bulk stress (or volume stress) | stress caused by compressive forces, in all directions | OpenStax | |||

center of gravity | point where the weight vector is attached | OpenStax | |||

compressibility | reciprocal of the bulk modulus | OpenStax | |||

compressive strain | strain that occurs when forces are contracting an object, causing its shortening | OpenStax | |||

compressive stress | stress caused by compressive forces, only in one direction | OpenStax | |||

elastic | object that comes back to its original size and shape when the load is no longer present | OpenStax | |||

elastic limit | stress value beyond which material no longer behaves elastically and becomes permanently deformed | OpenStax | |||

elastic modulus | proportionality constant in linear relation between stress and strain, in SI pascals | OpenStax | |||

equilibrium | body is in equilibrium when its linear and angular accelerations are both zero relative to an inertial frame of reference | OpenStax | |||

first equilibrium condition | expresses translational equilibrium; all external forces acting on the body balance out and their vector sum is zero | OpenStax | |||

gravitational torque | torque on the body caused by its weight; it occurs when the center of gravity of the body is not located on the axis of rotation | OpenStax | |||

linearity limit (proportionality limit) | largest stress value beyond which stress is no longer proportional to strain | OpenStax | |||

normal pressure | pressure of one atmosphere, serves as a reference level for pressure | OpenStax | |||

pascal (Pa) | SI unit of stress, SI unit of pressure | OpenStax | |||

plastic behavior | material deforms irreversibly, does not go back to its original shape and size when load is removed and stress vanishes | OpenStax | |||

pressure | force pressing in normal direction on a surface per the surface area, the bulk stress in fluids | OpenStax | |||

second equilibrium condition | expresses rotational equilibrium; all torques due to external forces acting on the body balance out and their vector sum is zero | OpenStax | |||

shear modulus | elastic modulus for shear stress | OpenStax | |||

shear strain | strain caused by shear stress | OpenStax | |||

shear stress | stress caused by shearing forces | OpenStax | |||

static equilibrium | body is in static equilibrium when it is at rest in our selected inertial frame of reference | OpenStax | |||

strain | dimensionless quantity that gives the amount of deformation of an object or medium under stress | OpenStax | |||

stress | quantity that contains information about the magnitude of force causing deformation, defined as force per unit area | OpenStax | |||

stress-strain diagram | graph showing the relationship between stress and strain, characteristic of a material | OpenStax | |||

tensile strain | strain under tensile stress, given as fractional change in length, which occurs when forces are stretching an object, causing its elongation | OpenStax | |||

tensile stress | stress caused by tensile forces, only in one direction, which occurs when forces are stretching an object, causing its elongation | OpenStax | |||

Young’s modulus | elastic modulus for tensile or compressive stress | OpenStax | |||

angular momentum | rotational analog of linear momentum, found by taking the product of moment of inertia and angular velocity | OpenStax | |||

law of conservation of angular momentum | angular momentum is conserved, that is, the initial angular momentum is equal to the final angular momentum when no external torque is applied to the system | OpenStax | |||

precession | circular motion of the pole of the axis of a spinning object around another axis due to a torque | OpenStax | |||

rolling motion | combination of rotational and translational motion with or without slipping | OpenStax | |||

angular acceleration | time rate of change of angular velocity | OpenStax | |||

angular position | angle a body has rotated through in a fixed coordinate system | OpenStax | |||

angular velocity | time rate of change of angular position | OpenStax | |||

instantaneous angular acceleration | derivative of angular velocity with respect to time | OpenStax | |||

instantaneous angular velocity | derivative of angular position with respect to time | OpenStax | |||

kinematics of rotational motion | describes the relationships among rotation angle, angular velocity, angular acceleration, and time | OpenStax | |||

lever arm | perpendicular distance from the line that the force vector lies on to a given axis | OpenStax | |||

linear mass density | the mass per unit length λ of a one dimensional object | OpenStax | |||

moment of inertia | rotational mass of rigid bodies that relates to how easy or hard it will be to change the angular velocity of the rotating rigid body | OpenStax | |||

Newton’s second law for rotation | sum of the torques on a rotating system equals its moment of inertia times its angular acceleration | OpenStax | |||

parallel axis | axis of rotation that is parallel to an axis about which the moment of inertia of an object is known | OpenStax | |||

parallel-axis theorem | if the moment of inertia is known for a given axis, it can be found for any axis parallel to it | OpenStax | |||

rotational dynamics | analysis of rotational motion using the net torque and moment of inertia to find the angular acceleration | OpenStax | |||

rotational kinetic energy | kinetic energy due to the rotation of an object; this is part of its total kinetic energy | OpenStax | |||

rotational work | work done on a rigid body due to the sum of the torques integrated over the angle through with the body rotates | OpenStax | |||

surface mass density | mass per unit area \(\sigma\) of a two dimensional object | OpenStax | |||

torque | cross product of a force and a lever arm to a given axis | OpenStax | |||

total linear acceleration | vector sum of the centripetal acceleration vector and the tangential acceleration vector | OpenStax | |||

work-energy theorem for rotation | the total rotational work done on a rigid body is equal to the change in rotational kinetic energy of the body | OpenStax | |||

center of mass | weighted average position of the mass | OpenStax | |||

closed system | system for which the mass is constant and the net external force on the system is zero | OpenStax | |||

elastic | collision that conserves kinetic energy | OpenStax | |||

explosion | single object breaks up into multiple objects; kinetic energy is not conserved in explosions | OpenStax | |||

external force | force applied to an extended object that changes the momentum of the extended object as a whole | OpenStax | |||

impulse | effect of applying a force on a system for a time interval; this time interval is usually small, but does not have to be | OpenStax | |||

impulse-momentum theorem | change of momentum of a system is equal to the impulse applied to the system | OpenStax | |||

inelastic | collision that does not conserve kinetic energy | OpenStax | |||

internal force | force that the simple particles that make up an extended object exert on each other. Internal forces can be attractive or repulsive | OpenStax | |||

Law of Conservation of Momentum | total momentum of a closed system cannot change | OpenStax | |||

linear mass density | \(\lambda\), expressed as the number of kilograms of material per meter | OpenStax | |||

momentum | measure of the quantity of motion that an object has; it takes into account both how fast the object is moving, and its mass; specifically, it is the product of mass and velocity; it is a vector quantity | OpenStax | |||

perfectly inelastic | collision after which all objects are motionless, the final kinetic energy is zero, and the loss of kinetic energy is a maximum | OpenStax | |||

rocket equation | derived by the Soviet physicist Konstantin Tsiolkovsky in 1897, it gives us the change of velocity that the rocket obtains from burning a mass of fuel that decreases the total rocket mass from mi down to m | OpenStax | |||

system | object or collection of objects whose motion is currently under investigation; however, your system is defined at the start of the problem, you must keep that definition for the entire problem | OpenStax | |||

conservative force | force that does work independent of path | OpenStax | |||

conserved quantity | one that cannot be created or destroyed, but may be transformed between different forms of itself | OpenStax | |||

energy conservation | total energy of an isolated system is constant | OpenStax | |||

equilibrium point | position where the assumed conservative, net force on a particle, given by the slope of its potential energy curve, is zero | OpenStax | |||

exact differential | is the total differential of a function and requires the use of partial derivatives if the function involves more than one dimension | OpenStax | |||

mechanical energy | sum of the kinetic and potential energies | OpenStax | |||

non-conservative force | force that does work that depends on path | OpenStax | |||

non-renewable | energy source that is not renewable, but is depleted by human consumption | OpenStax | |||

potential energy | function of position, energy possessed by an object relative to the system considered | OpenStax | |||

potential energy diagram | graph of a particle’s potential energy as a function of position | OpenStax | |||

potential energy difference | negative of the work done acting between two points in space | OpenStax | |||

renewable | energy source that is replenished by natural processes, over human time scales | OpenStax | |||

turning point | position where the velocity of a particle, in one-dimensional motion, changes sign | OpenStax | |||

average power | work done in a time interval divided by the time interval | OpenStax | |||

kinetic energy | energy of motion, one-half an object’s mass times the square of its speed | OpenStax | |||

net work | work done by all the forces acting on an object | OpenStax | |||

power | (or instantaneous power) rate of doing work | OpenStax | |||

work | done when a force acts on something that undergoes a displacement from one position to another | OpenStax | |||

work done by a force | integral, from the initial position to the final position, of the dot product of the force and the infinitesimal displacement along the path over which the force acts | OpenStax | |||

work-energy theorem | net work done on a particle is equal to the change in its kinetic energy | OpenStax | |||

banked curve | curve in a road that is sloping in a manner that helps a vehicle negotiate the curve | OpenStax | |||

centripetal force | any net force causing uniform circular motion | OpenStax | |||

Coriolis force | inertial force causing the apparent deflection of moving objects when viewed in a rotating frame of reference | OpenStax | |||

drag force | force that always opposes the motion of an object in a fluid; unlike simple friction, the drag force is proportional to some function of the velocity of the object in that fluid | OpenStax | |||

friction | force that opposes relative motion or attempts at motion between systems in contact | OpenStax | |||

ideal banking | sloping of a curve in a road, where the angle of the slope allows the vehicle to negotiate the curve at a certain speed without the aid of friction between the tires and the road; the net external force on the vehicle equals the horizontal centripetal force in the absence of friction | OpenStax | |||

inertial force | force that has no physical origin | OpenStax | |||

kinetic friction | force that opposes the motion of two systems that are in contact and moving relative to each other | OpenStax | |||

noninertial frame of reference | accelerated frame of reference | OpenStax | |||

static friction | force that opposes the motion of two systems that are in contact and are not moving relative to each other | OpenStax | |||

terminal velocity | constant velocity achieved by a falling object, which occurs when the weight of the object is balanced by the upward drag force | OpenStax | |||

dynamics | study of how forces affect the motion of objects and systems | OpenStax | |||

external force | force acting on an object or system that originates outside of the object or system | OpenStax | |||

force | push or pull on an object with a specific magnitude and direction; can be represented by vectors or expressed as a multiple of a standard force | OpenStax | |||

free fall | situation in which the only force acting on an object is gravity | OpenStax | |||

free-body diagram | sketch showing all external forces acting on an object or system; the system is represented by a single isolated point, and the forces are represented by vectors extending outward from that point | OpenStax | |||

Hooke's law | in a spring, a restoring force proportional to and in the opposite direction of the imposed displacement | OpenStax | |||

inertia | ability of an object to resist changes in its motion | OpenStax | |||

inertial reference frame | reference frame moving at constant velocity relative to an inertial frame is also inertial; a reference frame accelerating relative to an inertial frame is not inertial | OpenStax | |||

law of inertia | see Newton’s first law of motion | OpenStax | |||

net external force | vector sum of all external forces acting on an object or system; causes a mass to accelerate | OpenStax | |||

newton | SI unit of force; 1 N is the force needed to accelerate an object with a mass of 1 kg at a rate of 1 m/s2 | OpenStax | |||

Newton’s first law of motion | body at rest remains at rest or, if in motion, remains in motion at constant velocity unless acted on by a net external force; also known as the law of inertia | OpenStax | |||

Newton’s second law of motion | acceleration of a system is directly proportional to and in the same direction as the net external force acting on the system and is inversely proportional to its mass | OpenStax | |||

Newton’s third law of motion | whenever one body exerts a force on a second body, the first body experiences a force that is equal in magnitude and opposite in direction to the force that it exerts | OpenStax | |||

normal force | force supporting the weight of an object, or a load, that is perpendicular to the surface of contact between the load and its support; the surface applies this force to an object to support the weight of the object | OpenStax | |||

tension | pulling force that acts along a stretched flexible connector, such as a rope or cable | OpenStax | |||

thrust | reaction force that pushes a body forward in response to a backward force | OpenStax | |||

weight | force \(\vec{w}\) due to gravity acting on an object of mass m | OpenStax | |||

acceleration due to gravity | acceleration of an object as a result of gravity | OpenStax | |||

average acceleration | the rate of change in velocity; the change in velocity over time | OpenStax | |||

average speed | the total distance traveled divided by elapsed time | OpenStax | |||

average velocity | the displacement divided by the time over which displacement occurs | OpenStax | |||

displacement | the change in position of an object | OpenStax | |||

distance traveled | the total length of the path traveled between two positions | OpenStax | |||

elapsed time | the difference between the ending time and the beginning time | OpenStax | |||

free fall | the state of movement that results from gravitational force only | OpenStax | |||

instantaneous acceleration | acceleration at a specific point in time | OpenStax | |||

instantaneous speed | the absolute value of the instantaneous velocity | OpenStax | |||

instantaneous velocity | the velocity at a specific instant or time point | OpenStax | |||

kinematics | the description of motion through properties such as position, time, velocity, and acceleration | OpenStax | |||

position | the location of an object at a particular time | OpenStax | |||

total displacement | the sum of individual displacements over a given time period | OpenStax | |||

two-body pursuit problem | a kinematics problem in which the unknowns are calculated by solving the kinematic equations simultaneously for two moving objects | OpenStax | |||

acceleration vector | instantaneous acceleration found by taking the derivative of the velocity function with respect to time in unit vector notation | OpenStax | |||

angular frequency | \(\omega\), rate of change of an angle with which an object that is moving on a circular path | OpenStax | |||

centripetal acceleration | component of acceleration of an object moving in a circle that is directed radially inward toward the center of the circle | OpenStax | |||

displacement vector | vector from the initial position to a final position on a trajectory of a particle | OpenStax | |||

position vector | vector from the origin of a chosen coordinate system to the position of a particle in two- or threedimensional space | OpenStax | |||

projectile motion | motion of an object subject only to the acceleration of gravity | OpenStax | |||

range | maximum horizontal distance a projectile travels | OpenStax | |||

reference frame | coordinate system in which the position, velocity, and acceleration of an object at rest or moving is measured | OpenStax | |||

relative velocity | velocity of an object as observed from a particular reference frame, or the velocity of one reference frame with respect to another reference frame | OpenStax | |||

tangential accleration | magnitude of which is the time rate of change of speed. Its direction is tangent to the circle. | OpenStax | |||

time of flight | elapsed time a projectile is in the air | OpenStax | |||

total accleration | vector sum of centripetal and tangential accelerations | OpenStax | |||

trajectory | path of a projectile through the air | OpenStax | |||

velocity vector | vector that gives the instantaneous speed and direction of a particle; tangent to the trajectory | OpenStax | |||

accuracy | the degree to which a measured value agrees with an accepted reference value for that measurement | OpenStax | |||

base quantity | physical quantity chosen by convention and practical considerations such that all other physical quantities can be expressed as algebraic combinations of them | OpenStax | |||

base unit | standard for expressing the measurement of a base quantity within a particular system of units; defined by a particular procedure used to measure the corresponding base quantity | OpenStax | |||

conversion factor | a ratio that expresses how many of one unit are equal to another unit | OpenStax | |||

derived quantity | physical quantity defined using algebraic combinations of base quantities | OpenStax | |||

derived units | units that can be calculated using algebraic combinations of the fundamental units | OpenStax | |||

dimension | expression of the dependence of a physical quantity on the base quantities as a product of powers of symbols representing the base quantities; in general, the dimension of a quantity has the form \(L^{a} M^{b} T^{c} I^{d} \Theta^{e} N^{f} J^{g}\) for some powers a, b, c, d, e, f, and g | OpenStax | |||

dimensionally consistent | equation in which every term has the same dimensions and the arguments of any mathematical functions appearing in the equation are dimensionless | OpenStax | |||

dimensionless | quantity with a dimension of \(L^{0} M^{0} T^{0} I^{0} \Theta^{e} N^{0} J^{0}\)= 1; also called quantity of dimension 1 or a pure number | OpenStax | |||

discrepancy | the difference between the measured value and a given standard or expected value | OpenStax | |||

English units | system of measurement used in the United States; includes units of measure such as feet, gallons, and pounds | OpenStax | |||

estimation | using prior experience and sound physical reasoning to arrive at a rough idea of a quantity’s value; sometimes called an “order-of-magnitude approximation,” a “guesstimate,” a “back-of-the-envelope calculation”, or a “Fermi calculation” | OpenStax | |||

kilogram | SI unit for mass, abbreviated kg | OpenStax | |||

law | description, using concise language or a mathematical formula, of a generalized pattern in nature supported by scientific evidence and repeated experiments | OpenStax | |||

meter | SI unit for length, abbreviated m | OpenStax | |||

method of adding percents | the percent uncertainty in a quantity calculated by multiplication or division is the sum of the percent uncertainties in the items used to make the calculation | OpenStax | |||

metric system | system in which values can be calculated in factors of 10 | OpenStax | |||

model | representation of something often too difficult (or impossible) to display directly | OpenStax | |||

order of magnitude | the size of a quantity as it relates to a power of 10 | OpenStax | |||

percent uncertainty | the ratio of the uncertainty of a measurement to the measured value, expressed as a percentage | OpenStax | |||

physical quantity | characteristic or property of an object that can be measured or calculated from other measurements | OpenStax | |||

physics | science concerned with describing the interactions of energy, matter, space, and time; especially interested in what fundamental mechanisms underlie every phenomenon | OpenStax | |||

precision | the degree to which repeated measurements agree with each other | OpenStax | |||

second | the SI unit for time, abbreviated s | OpenStax | |||

SI units | the international system of units that scientists in most countries have agreed to use; includes units such as meters, liters, and grams | OpenStax | |||

significant figures | used to express the precision of a measuring tool used to measure a value | OpenStax | |||

theory | testable explanation for patterns in nature supported by scientific evidence and verified multiple times by various groups of researchers | OpenStax | |||

uncertainty | a quantitative measure of how much measured values deviate from one another | OpenStax | |||

units | standards used for expressing and comparing measurements | OpenStax | |||

anticommutative property | change in the order of operation introduces the minus sign | OpenStax | |||

antiparallel vectors | two vectors with directions that differ by 180° | OpenStax | |||

associative | terms can be grouped in any fashion | OpenStax | |||

commutative | operations can be performed in any order | OpenStax | |||

component form of a vector | a vector written as the vector sum of its components in terms of unit vectors | OpenStax | |||

corkscrew right-hand rule | a rule used to determine the direction of the vector product | OpenStax | |||

cross product | the result of the vector multiplication of vectors is a vector called a cross product; also called a vector product | OpenStax | |||

difference of two vectors | vector sum of the first vector with the vector antiparallel to the second | OpenStax | |||

direction angle | in a plane, an angle between the positive direction of the x-axis and the vector, measured counterclockwise from the axis to the vector | OpenStax | |||

displacement | change in position | OpenStax | |||

distributive | multiplication can be distributed over terms in summation | OpenStax | |||

dot product | the result of the scalar multiplication of two vectors is a scalar called a dot product; also called a scalar product | OpenStax | |||

equal vectors | two vectors are equal if and only if all their corresponding components are equal; alternately, two parallel vectors of equal magnitudes | OpenStax | |||

magnitude | length of a vector | OpenStax | |||

null vector | a vector with all its components equal to zero | OpenStax | |||

orthogonal vectors | two vectors with directions that differ by exactly 90°, synonymous with perpendicular vectors | OpenStax | |||

parallel vectors | two vectors with exactly the same direction angles | OpenStax | |||

parallelogram rule | geometric construction of the vector sum in a plane | OpenStax | |||

polar coordinate system | an orthogonal coordinate system where location in a plane is given by polar coordinates | OpenStax | |||

polar coordinates | a radial coordinate and an angle | OpenStax | |||

radical coordinate | distance to the origin in a polar coordinate system | OpenStax | |||

resultant vector | vector sum of two (or more) vectors | OpenStax | |||

scalar | a number, synonymous with a scalar quantity in physics | OpenStax | |||

scalar component | a number that multiplies a unit vector in a vector component of a vector | OpenStax | |||

scalar equation | equation in which the left-hand and right-hand sides are numbers | OpenStax | |||

scalar product | the result of the scalar multiplication of two vectors is a scalar called a scalar product; also called a dot product | OpenStax | |||

scalar quantity | quantity that can be specified completely by a single number with an appropriate physical unit | OpenStax | |||

tail-to-head geometric construction | geometric construction for drawing the resultant vector of many vectors | OpenStax | |||

unit vector | vector of a unit magnitude that specifies direction; has no physical unit | OpenStax | |||

unit vectors of the axes | unit vectors that define orthogonal directions in a plane or in space | OpenStax | |||

vector | mathematical object with magnitude and direction | OpenStax | |||

vector components | orthogonal components of a vector; a vector is the vector sum of its vector components | OpenStax | |||

vector equation | equation in which the left-hand and right-hand sides are vectors | OpenStax | |||

vector product | the result of the vector multiplication of vectors is a vector called a vector product; also called a cross product | OpenStax | |||

vector quantity | physical quantity described by a mathematical vector—that is, by specifying both its magnitude and its direction; synonymous with a vector in physics | OpenStax | |||

vector sum | resultant of the combination of two (or more) vectors | OpenStax |