Acceleration is the rate at which the velocity vector changes.

 

Accuracy - The agreement of a particular value with the true value.

 

 

Action-reaction pair – a pair of simultaneous equal but opposite forces resulting from the interaction of two objects

Adiabatic pressure - A process in which no heat is transferred to or from a system.

 

Alpha decay - A radioactive decay process in which an unstable nucleus emits an alpha particle.

 

Alpha particle - A particle emitted by some radioactive materials.  An alpha particle is a helium nucleus consisting of two protons and two neutrons.

 

Alternating current - A current in which the direction of electric charge flow changes regularly in an electric circuit.

 

Alternating Current - Electrical current in which charge flows back and forth, rapidly changing direction many times each second.

 

Ammeter -  A measuring instrument used to measure the electric current in a circuit. Electric currents are measured in amperes, hence the name.

 

Ampere - The unit of electrical current.  Defined as one coulomb per second.

 

Amplitude - The magnitude of a medium's displacement.

 

Angle of incidence - The angle between an incident ray and the normal to the surface.

 

Angle of reflection - The angle between a reflected ray and the normal to the surface.

 

Angle of refraction - The angle between a refracted ray and the normal to the surface.

 

Angular acceleration - The ratio of the change in angular speed to the time interval over which the change is measured. 

 

Angular displacement - The change in angular position, or angular distance traveled, when an object rotates from one position to another.

 

Angular impulse - The product of the torque exerted on an object and the time interval over which the torque acts.

 

Angular momentum - The product of rotational inertia and rotational velocity.

 

Angular Speed- The ratio of angular displacement to the time interval over which the displacement is measured.

 

Anode - Negative electrode.

 

Antinode – The point of largest amplitude when two wave pulses meet of two superimposed waves.

 

Archimedes' principle - An object immersed in a fluid has an upward (bouyant) force exerted on it equal to the weight of the fluid displaced by the object.

 

Archimedes’s Principle: The buoyant force on an object in a fluid is equal to the weight of the displaced fluid.

 

Atmospheric pressure - The pressure exerted by the weight of an air column that extends from the Earth's surface to the outer layers of the atmosphere.

 

Atomic mass unit - A unit of mass used for nuclear calculations.  Defined as 1/12 the mass of the carbon-12 isotope.

 

Atomic number - The number of protons in the nucleus of an atom.

 

Average acceleration - The ratio of the change in velocity to the time interval over which the distance is measured.

 

Average speed - The ratio of the total distance traveled to the time interval over which the distance is measured.

Average Velocity- The ratio of the displacement to the time interval over which the displacement is measured. 

 

 

Back emf – the emf induced in a motor’s coil that tends to reduce the current powering the motor

 

Background radiation - The nuclear radiation that arises naturally from cosmic rays and from radioactive  isotopes in the soil and air.

 

Balanced forces - When a number of forces act on a body, and the resultant force is zero, then the forces are said to be balanced forces.

 

 

Band gap – the minimum energy separation between the highest occupied state and the lowest empty state

 

Barometer - An instrument used to measure atmospheric pressure.

 

Battery - A group of galvanic cells connected in series. 

 

Beam divergence - A measurement of how much a laser beam spreads as it travels through air.

 

Beat - A pattern of pulsations or variations in loudness produced by two sound waves having slightly different frequencies.

 

Bernoulli's principle - As the velocity of a fluid increases, the pressure in the fluid decreases. 

 

Beta decay - A radioactive decay process in which an unstable nucleus emits a beta particle.

 

Beta particle - A charged particle emitted as a product of radioactive decay.

 

Binding energy - The energy holding the protons and neutrons together in the nucleus of an atom.

 

Binocularity - the ability to focus on an object with both eyes to create a single stereoscopic image.

 

 

Blackbody radiation – electromagnetic radiation emitted by a blackbody, which absorbs all incoming radiation and then emits radiation based only on its temperature

 

 

  Block and Tackle – a group of pulleys

Bohr frequency condition- A condition in which an electron in an atom jumps from one energy level to another and a photon is emitted.

Boiling point - Temperature at which a substance changes state from liquid to gas.

 

BTU (British Thermal Unit) - A basic measure of thermal (heat) energy. One BTU is the amount of energy needed to heat one pound of water one degree Fahrenheit, measured at its heaviest point.

 

Buoyant force - The net upward force exerted by a fluid on a submerged or immersed object.

 

Calorie - A unit of heat.  One calorie is the heat required to raise the temperature of one gram of water one degree Celsius.

 

calorie:             The amount of energy required to change the temperature of one gram (one milliliter) of water one degree Celsius.  Because this energy is so small, kilocalories are used for food applications.

 

Capacitance - The ratio of the charge stored on a capacitor to the potential difference across the capacitor.  

 

Capacitor - An electrical device that stores charge and energy.  The energy is stored in the electric field across the plates of a charged capacitor.

 

Carnot efficiency - The maximum possible efficiency of a heat engine.

 

Cathode - Positive electrode.

 

Center of Mass - the point at which the entire mass of the object can be considered to be concentrated

 

CTE - Career and Technical Education.

 

Chain reaction- A process of self sustained fission reaction in which neutrons are absorbed and cause fissions. 

Charge - Charges are the basis of electricity. A charge exerts force on other charges. The smallest charge is the charge of an electron: 0.000000000000000016 Coulombs.

 

Circular motion - The motion of a body along a circular path. 

 

Closed system- A system that does not gain or lose mass (2.2, 5.2, and 7.1)

 

Coefficient of Friction- The ratio of the maximum force of friction to the normal force between the surfaces in contact. 

Coherent wave- waves that are in the same

 

Compression – a portion of a longitudinal wave in which the molecules are close together.  In a sound wave,  it is a region of increased air density and pressure.

 

Concave Lens – A diverging lens, thicker at its outer edge than at its center.

 

Concave Mirror- A mirror with an inwardly curved surface (“caved in”) as seen by an incident light ray (10.1)

 

Conduction – The process that transfers kinetic energy when particles collide.

 

 

Conductor - Material through which heat can be transferred.  When referring to electricity, a conductor is a material through which an electric current can flow.

 

Constructive interference: phenomenon in which the interaction of two in-phase waves produces an increase (amplification) in wave amplitude.

 

Constructive interference - Phenomenon in which the interaction of two waves produces a decrease in wave amplitude.

Critical angle- The angle of incidence for a light ray traveling through a material for which the refracted angle has a measure of 90 degrees.

 

Destructive interference: phenomenon in which the interaction of two waves, of equal frequency & amplitude and out of phase from each other by 180^o, produces a decrease (cancellation) in wave amplitude.

 

 

http://static.howstuffworks.com/gif/butterfly-color-interference.gif

 

Context - Surrounding conditions: the circumstances or events that form the environment within which something exists or takes place.

 

Convection - The transfer of heat through direct contact.

 

Convex lens - A transparent material that is formed into a shape that has two surfaces.  It is thicker at its center than at its edges.  It is also called a converging lens because rays of light that pass through it converge.

 

Coulomb (C) - SI unit for charge.

 

Coulomb’s law - One charged object attracts another charged object with a force that is directly proportional to the product of the objects’ charges and inversely proportional to the square of the distance between the objects’ centers.

 

Crest - The point of maximum positive displacement on a transverse wave.

 

Critical Angle - the angle of incidence at which a light ray will be bent so that the angle of refraction is 90 degrees.

 

Current (I) - The rate of flow of electrical charge.

 

Density – A property of a material, defined as the mass of a sample per unit of volume.  (Mass divided by volume.)

 

Destructive interference - Phenomenon in which the interaction of two waves produces an increase in wave amplitude.

 

Diffraction- The bending of light around the edges of an obstacle (10.2)

Diffraction Grating- An optical device that uses a large number of parallel slits (or lines) to transmit (or reflect) light to form an interference pattern.

 

Direct current - A current in which electric charge flows in one direction in an electric circuit.

 

Distance - One of the undefined qualities of physics, it measures the separation of two points.

 

Displacement - A vector quantity; the distance and direction through which an object moves.

 

 

1)      Displacement:  a vector that points from an object’s initial position to its final position and has magnitude that equals the shortest distance between the two positions.

 

Dependent variable - When two variables are related, we say that one depends on the other. This variable is called the dependent variable. The "other" variable is free to roam so it is called the independent variable. In a scientific experiment, the experimenter chooses values for the independent variable, runs the experiment, and measures the dependent variable. Ordered pairs of chosen and measured values (independent and dependent) are often plotted on a two-dimensional graph for visualization. The dependent variable is traditionally plotted on the vertical axis.

 

Drag - The force that resists motion of an object moving through a fluid or a fluid moving past a stationary object.

 

Efficiency - The ratio of output work to input work.

Elasticity- The tendency of an object or material to return to its original shape after being stretched or compressed.

Elastic potential energy- Energy stored by an object due to a change in its shape. 

Electricity: The Flow of Electrons

 

Electromagnetic induction- The process of generating a current in a wire due to relative motion between the wire and a magnetic field.

 

 

Electromagnetic spectrum - The range of electromagnetic waves extending from radio waves to gamma rays.

Electromechanical device -  A device that converts electrical energy into mechanical energy in order to do work.

 

Elementary charge - Charge on one electron or proton, it is 1.60 x 10-19.

 

Electric field – An imaginary construction of vectors to help us visualize and predict electric forces on charged objects placed in the fields.

Energy (E) - Allows a body to do work; ability to cause a change. Measured in Joules = Newton-meters.  The energy of an object increases when work is done on it.  An increase in energy may heat up the object, speed it up, lift it up, or all of the above.

 

 

Energy –  A system’s potential to perform work OR moving a system through a “displacement- like” quantity with a Prime Mover.  During any closed-system interaction, mechanical energy is conserved (Etotal = K + U) or (Etotal = KE + PE), depending upon your experience levels with Physics.  If the system is open to outside forces, other energies can come into the equations, such as Elastic Potential and Thermal Potential.

 

Equilibrium - A state in which the net force acting on an object is zero; or when the forces are balanced.

 

Evaporator - A device used to remove water (usually by providing heat).

 

First class lever - A type of simple of machine in which the fulcrum is positioned between the resistance and the effort forces.  It is generally used to multiply force, but if a large effort is used on the shorter lever arm, it can also be used to multiply distance.  Scissors are an example of a first class lever.

 

First law of thermodynamics - Law stating that the increase in internal energy of a system is the heat added to the system minus the work done by the system.

 

 

1)      Fluid:  any substance that can flow and has no definite shape of its own.  As a result a fluid will take on the shape of its container.  Fluids are liquids and gases.

 

Fluid resistance - A measure of the ability of an object to oppose the flow of fluid across the object's surface.  Defined as the ratio of the pressure drop in the fluid to the volume of flow rate.

 

Fluid system - A system in which a fluid (air, steam, water, oil, etc.) is moved through pipes, lines or tubes.

 

Focal length - A measure of the distance from the lens to the focal point of the lens, or a measure of how strongly a lens converges or diffuses light.

 

focal point- the point in front of the mirror at which the reflected rays all meet.

 

Foot (ft) – The base unit of length in the English system.

 

Force (F) - A push or pull on an object.  The strength of a force is defined by the rate at which it can speed up one kilogram of mass.

 

 

 

 

Free-body diagram - A pictorial representation of all the forces that act on a body or system which move as a single unit.

 

Frequency - The number of repetitions of a cycle in a period of time. The Hertz is the unit of measurement when the time is measured in seconds.  It is a rate of occurrence of a cycle. 

 

 

Friction - Force that opposes relative motion of two solids or a solid and a liquid.

 

Fuse - An electrical device containing a metal strip that melts when current in the circuit becomes too great.

 

 

Fusion -  A union in which two light nuclei combine to form a single heavier nucleus plus energy.

 

 

Galvanic cell - a device in which chemical energy from a spontaneous redox (oxidation-reduction) reaction is changed to electrical energy that can be used to do work.

 

Gamma ray - The highest energy form of electromagnetic radiation.  Gamma rays are between 10^-13 and 10^-11 meters in wavelength.

 

Gage pressure - The measure of pressure above or below atmospheric pressure.

 

 

Generator-  A device that converts rotating mechanical energy into electrical energy; found in power plants.

 

 

Gravitational Force – An attractive force acting at a distance between two or more masses.

 

 

Half-life - The time required for half a sample of radioactive nuclei to decay. 

 

 

Head-to-tail method of vector addition - The process of combining two or more vectors.  If the vectors are at any angle other than the same or the opposite from each other, a triangle must be drawn.  Draw one vector and then at its head begin drawing the other vector.  The resultant vector is drawn from the tail of the first one to the head of the second vector.  The resultant represents the single short-cut vector that would accomplish the same result as the two vectors.

 

Heat - The energy that flows from one object to another because of a temperature difference.

Heat flow rate -  The rate at which heat transfers between bodies.

 

Heat of fusion – The amount of energy required to melt one gram of a solid substance.  Also, the amount of energy released when one gram of a liquid solidifies.

 

Heat of vaporization -- The amount of Thermal Energy (expressed in calories) required to vaporize one gram of a liquid material into a gas (or condense a vapor back into a liquid).  The formula for E_v = (mass)(latent heat of vaporization).  Each material has its own unique latent energy constant.  When dumped into a liquid, this energy is stored as Potential Energy for the substance.  When released by the vapor, this released energy becomes Kinetic Energy.

 

Heat - Energy that flows from one object to another because of a temperature difference; it is not the same thing as thermal energy since it must be transferring to be heat.

 

Heat - Energy as it flows from one object to another due to a temperature difference.

 

 

1)      Heat:  energy that flows from an object with a greater kinetic energy per molecule (higher temperature) to an object of less kinetic energy per molecule (lower temperature) because of a difference in average kinetic energy per molecule (temperature).

 

Henry --- the unit of inductance. Defined as one volt per ampere per second.

 

Hertz --- the unit of measure of frequency. Defined as one cycle per second, or 1/s.

 

Horsepower --- an English unit of power. Defined as 550 foot pounds per second.

 

Hydraulic system --- A system that uses a liquid as a working fluid

Hyperopia  ( Farsightedness ) - the ability to see things better at a distance. Near objects appear blurred because the parallel light rays coming into the eye

                                              are focused behind the retina, instead of directly on the retina.

 

Independent variable - When two variables are related, one of the variables is free to roam so it is called the independent variable. The other variable depends on the first, so it gets the name dependent. In a scientific experiment, the experimenter chooses values for the independent variable, runs the experiment, and then measures the dependent variable. Ordered pairs of chosen and measured values (independent and dependent) are often plotted on a two-dimensional graph for visualization. The independent variable is traditionally plotted on the horizontal axis.

 

Infrared radiation - Electromagnetic waves in the wavelength band between approximately 10-6m and 10-3m that can be used to transfer heat from a hot object to a cool object.

 

Index of refraction - Measure of how much the speed of a wave is reduced inside the medium.

 

 

Impedance - The total opposition to alternating current flow in a circuit.

 

Impact - The force on an object that changes its momentum.  For a given change in momentum, the longer the impact lasts, the smaller the impact needs to be to make the change.  The shorter the time interval, the larger the impact needs to be for the change to occur. 

 

Impulse - The change in momentum, where the impact force is multiplied by the duration of the impact.  Impulse causes the momentum to change. 

 

Inertia - The resistance of an object to a change in motion, whether speeding up, slowing down, starting, stopping, and/or changing direction (acceleration).  It is represented by the mass (rest) of the object, as opposed to momentum where inertia is modified by velocity.

 

Isolated system- A closed system on which no net external force act.

 

Isothermal process –  A change in which the temperature of the system remains constant.

 

Isotopes – Atoms that have the same number of protons in their nuclei but differing numbers of neutrons.

 

James Beltran's PT Glossary Terms

 

Joule (J) – The SI unit of energy. Equal to one Newton-meter.

 

Kelvin (K) – The interval of temperature measurement on the Kelvin scale. 

Kilogram - The principal SI unit of measure for mass, abbreviated kg.

 

Kinetic energy (K) - Notice that this energy of motion is proportional to the square of the speed. The unit of Joule may also be expressed as kg(m/sec)(m/sec). (Energy of motion.)

 

Laminar flow - Fluid moving in parallel layers with no disruptions between layers.  Also called streamlined flow and is characterized by flow which is slow and smooth.

 

Laser - An electrical device that produces (1) monochromatic, (2) highly directional and (3) coherent light. Expanding this simple definition based on the Physics in Context, page 477: The light is monochromatic since the emitted photons have the same energy as stimulating photons and emitted photons are used to stimulate emission, all photons in the laser beam have the same energy and, therefore, wavelength. The light is highly directional since emitted photons travel in the same direction as stimulating photons; so all photons in the laser beam have the same direction. Note: If not for diffraction caused by the exit aperture of the laser device, the beam would be almost perfectly parallel. The light is coherent since emitted photons are in phase with stimulating photons. The light waves travel in phase, with crests traveling with crests, troughs traveling with troughs.

 

Laser Medium- A solid, liquid or gaseous material that can be used to amplify the intensity of a laser beam.

 

    Law of Conservation of Angular Momentum – When no net external torque acts on a closed system, the total angular momentum of the system remains constant.

    Law of Conservation of Energy -  The total energy of an isolated system is constant.

    Law of Conservation of Linear Momentum – When no net external force acts on a closed system, the total linear momentum of the system remains constant.

    Law of Reflection – When light reflects from a surface, the angle of reflection equals the angle of incidence.

    Newtons’ First Law of Motion – If the net force on an object or a system is zero, the velocity of the object or system will not change.

 

 

Lens - A transparent material that can bend parallel rays of light so that they cross or appear to cross at a single point.

 

Lever - A bar that is free to pivot on a fixed point, or fulcrum; a lever is a simple machine.

 

Lever arm – The shortest distance from an object’s axis of rotation to the line of action of an applied force.

 

Longitudinal wave - A wave that displaces particles in the medium parallel to the direction in which the wave travels.

 

Linear momentum - The product of an object's mass and its velocity.  Linear momentum is a vector quantity.

 

Machine – A device that changes the magnitude or the direction of a force needed to do work, making the task easier to accomplish.

 

 

Magnetic Field – An imaginary construction of vectors to help us visualize and predict magnetic forces on charged objects moving through the field.

 

Magnetic poles - The ends, or sides, of a magnet about which the force of magnetic attraction seems to be concentrated.

 

 

Magnetic Confinement Fusion - is a process that uses a large magnetic field to heat and confine the reactants of a nuclear fusion reaction long enough to achieve fusion without being in contact with another material.

 

Magnification – The ratio of the image size to the object size in an optical system.

 

 

Mass (M) - One of the undefined qualities of physics, mass is the measure of inertia.

 

 

Mass Defect- is the difference in the total mass of the reactants and products of a nuclear reaction. The mass defect represents the amount of binding energy absorbed or released during the nuclear reaction.

 

Mass Flow Rate – The ratio of the change is mass to the time interval over which the change is measured.

 

Mass Number – The number of nucleons (protons plus neutrons) in the nucleus of an atom.

 

Mechanical advantage:  The ratio of the output force to the input force, usually in reference to a simple machine.  

 

 

 

Moment of inertia - A property of matter that describes an object's resistance to rotational motion.

 

Moment of Inertia:  The resistance of an object to change its state of rotation.  It is proportional to the mass of the object and the square of the effective radius of the object.

 

 

Momentum –    An object’s quantity of motion based upon its mass and velocity.  Additionally, this quantity is conserved through all collisions, whether elastic or inelastic; this means it is fully transferable from object to object.

 

Myopia  ( Nearsightedness ) - the ability to see things better up close than at a distance. Distant objects appear blurred because the parallel light rays coming

                                             into the eye are focused in front of retina, instead of directly on the retina.

 

 

Motor-  A device that converts electrical energy into rotating mechanical energy; found in power tools.

 

Natural frequency - The frequency at which a particular object vibrates.

 

Net force - The overall force acting on an object, when all the individual forces acting on the object are added together.

 

Nuclear force - The interaction that binds protons and neutrons together in a nucleus.

 

 

Nuclear Fusion – is a nuclear reaction in which multiple nuclei join together to form a heavier nucleus. It is accompanied by the release or absorption of energy. This energy is called the binding energy.

 

Nuclear Radiation – A transfer of energy away from an unstable nucleus by means of alpha particles, beta particles, or gamma rays.

 

Physics - The science of matter and energy and of interactions between the two, grouped in traditional fields such as acoustics, optics, mechanics, thermodynamics, and electromagnetism, as well as in modern extensions including atomic and nuclear physics, cryogenics, solid-state physics, particle physics, and plasma physics.

 

PIC - Physics in Context, the title of the textbook approved for the PT course.

 

PT - Principles of Technology; it is the name of the course and also the name of one set of textbooks for the course.

 

Plane mirror- Mirrors with flat surfaces.

 

Plane of Incidence- The plane where the incident ray, the normal and

the reflected ray all lie in the same plane.

 

 

Plasma - A very hot (over 2000^o C) gas that contains free electrons and ions.  Plasmas are not very common on Earth, but are the most common state of matter in the universe.

 

Position - The position of an object is its distance from zero. The position depends on the zero (origin) of the measurement. The identification of an object’s location in space.

 

 

Positron- One type of particle emitted during Beta decay. Positrons are identical to electrons in size and mass but have a positive charge. A Positron is an example an antiparticle, a particle of antimatter.

 

Potential difference - The amount of work that would need to be done on a unit of electric charge to move it from one point to the other against an electric field; is synonymous with voltage and is measured in volts.

 

Potential energy - Energy due to an object's position.

 

Power (P) - Power is the rate of working. When power is transmitted electrically, the amount is the product of voltage (V) with current (I).

 

Power- Power is the rate of doing work. This means how much work can be done in a certain amount of time. The equation is Pwr= W/t   Power = work divided by time.  You can also say (force x distance) /time.  Pwr=Fd/t   

 

Units                                                                                                                                                                                                                 

 

English	SI
hp = horsepower           1 hp= 550 ft-lbs/s = 746 W	W=Watts    W = j/s = joules/sec
Ft-lbs = foot pounds

  

 

 

Precision -  The degree of agreement among several measurements of the same quantity; the reproducibility of a measurement. 

 

Presbyopia - normal aging process that involves the loss of elasticity/ flexiblity of the lens in the eye making it hard to focus sharply at near objects.

 

Pressure -  The amount of force exerted per unit of area; P = F/A.

 

Pressure- Defined as the force divided by the area over which it acts.  It is the prime mover in a fluid system.

 

 

Prime Mover –  A “force-like” quantity which causes motion [change in position] within a system.  Within a Mechanical System, this PM is either Force or Torque, depending on a linear- or rotational-based system.

 

Prime mover - The entity responsible for motion in an energy system...force in mechanical systems, pressure in fluid systems, potential difference (voltage) in electrical systems, temperature difference in thermal systems.

 

Principle - A fundamental, primary, or general law or truth from which others are derived.

 

Principle of conservation of charge - The net electric charge in an isolated system never changes.

 

Projectile - An object thrown into space either horizontally or at an acute angle and under the action of gravity is called a projectile. The path followed by a projectile is called its trajectory. The horizontal distance traveled by a projectile is called its range. The time taken by a projectile from the moment it is thrown until it touches the ground is called its time of flight. 

 

Property - A quality or trait belonging to an object or system.

 

Propogate - To travel through space or throughout a material.

 

PT Glossary Terms-Rick Mills

 

 

Pulley – a simple machine that contains a wheel with a grooved rim in which a rope runs through

Radian - A unit of angle measurement where the radius of a circle is equal to the length of the arc on the circle.  It is about 57.3^o.

 

Radiation - The transfer of energy by electromagnetic waves.

 

Radioactivity - Process by which an unstable nucleus emits one or more particles or energy in the form of electromagnetic radiation.

 

Radio wave - The lowest energy form of electromagnetic radiation.  Radio waves are between about 1 and 10⁶ meters in wavelength.

 

Rarefaction – a portion of a longitudinal wave in which the molecules are spread out.  In a sound wave,  it is a region of decreased air density and pressure.

 

Ray Diagram -  a diagram which traces the path which light takes in order for a person to view a point on an image or an object

 

Refraction – change in direction of a wave when it crosses a boundary between different mediums

 

 

ray optics-  the study of light motion in optical systems using rays.

 

real image- when light strikes a mirror, reflects through the focal point with light rays converging from the object. This image can be seen by placing a screen or piece of paper at the point of converging light rays.

 

 

 

 

Resultant vector – a single vector representing the sum of two or more addend vectors.

 

Scalar - A physical quantity described by magnitude only; e.g.,mass.

 

Second: The base unit of time in the SI and English systems.

 

Second Law of thermodynamics: (1) The natural direction of heat flow is from high-temperature to a low-temperature body. (2) A heat engine can convert only some of the heat taken from a reservoir into work.  The rest is rejected as heat at a lower temperature.

 

Semiconductor - A material intermediate between a conductor and an insulator in its ability to conduct charge.

 

Series circuit - An electrical circuit in which there is only one path for current.  Charge flows through each device in the circuit one at a time.

 

 

 

SI System – measurement system used in Science; based on powers of ten

 

Slug --- The base unit of mass in the English system

 

Slug: the base unit of mass in the English system if measurements (equivalent to the mass that is accelerated at the rate of one foot per second per second when acted on by a force of one pound weight).

 

Snell’s Law - The ratio of the sines of the angle of incidence and refraction equals the inverse ratio of the indices of refraction. This can also be written as the index of refraction times the sine of angle of incidence is equal to the second index of refraction times the sine of the angle of refraction. Sinθ₁/sinθ₂ = n₂/n₁ or                 n₁sinθ₁ = n₂sinθ_{2  .}

 

 

Snell's Law- displays the relationship between angles of incidence and refraction.

 

 

solenoid - A series of loops of wire that acts like a magnet when a current flows through it. 

 

Specific heat - The amount of energy that must be added to raise the temperature of one unit mass of a substance by one temperature unit.

 

Specific gravity - A dimensionless number that compares the density of a substance to the density of water.

 

 

spectrum-  range of frequencies that characterize light

 

Speed - Speed is simply the rate of position change, but for analysis and problem solving speed has several faces. The speed at an instant can be approximated with an average speed measured over a short time interval. Initial speed is the speed of an object at the beginning of a measurement, an intial condition. The average speed is the ratio of distance covered to the time it takes, or the average of the final and intial speeds. The change in speed is the difference between final and inital speeds. The symbol v is used for speed because speed is the size of the velocity vector.  It is the distance an object moves (change in position - represented by ∆d) within a certain time period. You calculate speed by dividing the distance or (∆d) an object traveled by the time or (∆t) required to travel that distance. The SI units for speed include meter per second (m/s) or kilometer per hour (km/hr). The formula is

Thermodynamics - A branch of physics and of chemistry that studies the effects of changes in temperature, pressure and volume on physical systems.

 

Thermometer: A device that Measures temperature.

 

Time (T) - One of the undefined qualities of physics. We all know what it is and agree to use a second as one unit of time.

 

Time interval – the elapsed time or the difference between two clock readings.

 

Torque - A quantity that causes rotation in mechanical systems.

 

Total internal reflection -   when an incident ray strikes a boundary of a medium with a lower index of refraction

at a large enough angle so no light is refracted                                                                                                                                                                                                                                                                                                                                                                                     

 

Transverse wave - A transfer of energy such that the direction of the displacement of the medium is at right angles to the direction of energy flow.  Water waves are an example.

 

Trough - One of the places in a wave where the wave is the lowest, or the disturbance is the greatest, in the opposite direction from a crest.

 

Turbulent flow - Irregular flow of fluid over a surface, with eddies and whorls causing fluid to move in different directions.

 

Ultraviolet radiation – electromagnetic waves in the wavelength band between approximately 10^-9m and 10^-7 m

 

 

Unit- A letter or symbol that represents a dimension that is appended to a numerical value to indicate the scale of the measurement.

 

 

Vacuum -  A volume of space that is empty of matter such that its gaseous pressure is less than atmospheric pressure.

 

Variable- A letter or symbol that represents a factor that is subject to change and is currently undefined.

 

 

Virtual image – an image that causes light to diverge from a mirror or lens.  This type of image cannot be seen on a backdrop.

Viscosity - The property of a fluid that describes the resistance to flow. The resistance to flow is due to internal friction between the molecules (or atoms).  

 

Visible light - Electromagnetic waves that can be detected by the human eye with a wavelength between 400 nm and 700 nm.

 

Volt (V) – the unit of measure of electric potential difference.

 

 

Voltage - A force created by a buildup of charge. 

 

Voltage (V) - Voltage is an energy measure, the energy carried by one coulomb of electrical charge. The voltage between two points in a circuit is the amount of energy available for pushing each coulomb of charge from one of these points to the other.

 

Voltmeter - An instrument used for measuring the electrical potential difference between two points in an electric circuit.

 

Volume flow rate - Equals the cross sectional area x linear speed.

 

Watt (W) - The SI unit of power, defined as one joule per second, the rate at which work is done.

 

Wavelength (λ) - The distance between corresponding wave points; the shortest distance between repeating wave patterns. This distance is measured in meters, or portions of meters.

 

Wave pulse - A disturbance moving through a medium or field.

 

Weight - Force of Earth’s gravity acting downward on an object’s mass.

 

Weight -  A force caused by Earth's gravity.  It is the product of an object's mass and the acceleration of gravity.

 

 

1)      Weight:  gravitational force that the Earth exerts on an object.  The weight always acts downward, toward the center of the Earth.

 

Weight Density – a property of a material, defined as the weight of a sample of the material divided by the volume.

 

Work (W) - Work is done on an object whenever it moves because it is pushed or pulled. Work increases the energy of the object.  The amount of energy gained or lost by an object when a force moves the object through a distance.  Defined as the product of the force applied (in the direction of the motion) and the distance the object moves.

 

 

1)      Work:  amount of energy gained or lost by an object when a force moves the object through a distance where the force and motion are in the same direction.  W=Fcosd (W=work, F=magnitude of the force, angle between the force and the displacement, d=displacement)

 

 

 

Work-energy theorem - the work done on an object equals the change in kinetic energy of the object.

 

Work function - Energy needed to remove an electron from metal.

 

Wave types and Associated wavelengths
Wave type	Starting Wavelength (m)	Ending Wavelength (m)
1. Radio	10-7	10-1
2. Microwave	10-2	10-4
3. Light	10-4	10-8
4. X-Ray	10-8	10-11
5. Gamma	10-11	10-13
6. Cosmic	10-13	10-16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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