Classical Mechanics
Classical Mechanics is a branch of physics that deals with the motion of objects and the forces that cause this motion of bodies in accordance with the general principles by Isaac Newton's laws of mechanics. It is concerned with the behavior of objects at speeds that are much less than the speed of light and sizes that are much larger than atomic dimensions. Classical Mechanics was first formulated by Sir Isaac Newton in the late 17th century and is also known as Newtonian mechanics. Classical mechanics gives accurate results as long as it is limited to large objects and the speeds less than the speed of light.
Classical Mechanics has many practical applications in engineering, such as in the design and analysis of structures, vehicles, and machines. It is also used in astronomy, where it is used to predict the motion of celestial bodies, and in the study of the behavior of fluids, where it is used to predict the flow of fluids.
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Classical mechanics Glossary
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 Abrasion  The destruction of a material caused by scraping or rubbing against a rough, hard surface.
 Abrasion Resistance  The ability to withstand scuffing, scratching, rubbing or deterioration due to physical contact.
 Abrasive  A material that is able to remove the surface of another material.
 Absolute Roughness  A measure of the roughness of the inside of a flowing pipe.
 Absolute Vacuum  Contains no matter and can not be achieved.
 Acceleration  The rate of change of velocity. Whenever a mass experiences a force, an acceleration is acting.
 Acceleration due to Gravity  The force on an object caused only by gravity.

Acceleration from Force  The mass and the net forces acting on the object.
 Acceleration of Gravity  The force on an object caused only by gravity.
 Affinity Laws  Express the mathematical relationship between the several variables involved in pump performance.
 Air Resistance  A force that opposes an object as it moves through the air.
 Allowable Stress  The maximum stress that a material can safely withstand under specific operating conditions.
 Angular Acceleration  The rate at which the angle velocity changes with respect to time.
 Angular Deflection  When a flex connector is bent on it's centerline. One end of the hose assembly is deflected or bent with the other end remaining parallel.
 Angular Displacement  The angle through which a body moves in a circular path.

Angular Momentum  How much an object is rotating around a fixed point.
 Angular Momentum of an Object with Linear Momentum  The porportion of the average net torque and the time interval the torque is applied to.
 Angular Velocity  The speed that an object moves through an angle, θ. The calculation below calculates ω but does not calculate the relative velocity of a point as it moves throughout the curve.
 Angular Speed  The speed that an object moves through an angle, θ. The calculation below calculates ω but does not calculate the relative velocity of a point as it moves throughout the curve.

Angular Velocity of a Rolling Sphere  Without slipping is the velocity of a point on the circumference (relative to the center of the sphere), divided by the radius of the sphere.

API Gravity  If a fluids API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks.
 Applied Force  Can come from different types of forces, one of them could be Newton's Second Law.
 Area Moment of Inertia  The resistance of an object to bend around a certain axis of a area crosssection.
 Atmospheric Pressure  The pressure exerted upon the earth's surface by the air because of the gravitational attraction of the earth.
 Average Acceleration  The change of velocity over an elapsed amount of time. Whereas, instantaneous accleration is the change of velocity at a specific point in time.
 Average Angular Acceleration  The average rate at which the angle velocity changes with respect to time.
 Average Angular Velocity Change in Velocity  When an object makes changes in its angular velocity at different times that is an average angular velocity of any given velocities.
 Average Velovity Change in Velovity  When an object make changes in its velocity at different times that is an average velocity of any given velocities.
 Axial Deflection  When a flex connector is compressed or stretched on it's centerline which usually occurs from the change in temperature.
 Axial Force  The force acting parallel to the longitudinal xaxis. Also called shear force.

Axial Stiffness  The ratio of the axlal load to axial deflection. An axial load happens when a force is applied parallel to the axis of another object.
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 Beam Shear Stress  The horizontal shear stress of a beam.
 Breakaway Torque  The torque necessary to put into reverse rotation a bolt that has not been tightened.
 Breakloose Torque  The torque required to effect reverse rotation when a prestressed threaded assembly is loosened.
 Brinell Hardness Number  A value assigned to the hardness of metals and alloys.
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 Centrifugal Acceleration  The motion of an object traveling in a circular path with respect to time.

Centrifugal Force  When a force pushes away from the center of a circle, but this does not really exist.
 Centripetal Acceleration  The change in the velocity, which is a vector, either in speed or direction as an object makes its way around a circular path.
 Centripetal Force  The force that makes an object follow a curved path. It is a force generated when an object keeps traveling along a axis of rotation.
 Change in Angular Momentum  The porportion of the average net torque and the time interval the torque is applied to.
 Characteristic Length  A dimension used in physics that defines the scale of a physical system.
 Characteristic Time  An estimate of the order of magnitude to the reaction time scale of a system.
 Characteristic Velocity  Measure the effectiveness of the combustion of a rocket engine at high temperature and pressure, seperate from nozzle performance.
 Circular Velocity  The velocity at which an object moves around a circle with a given radius.
 Coefficient of Friction  The ratio between two contacting surfaces and the frictional force that resists the normal force of the object.
 Collinear Force  All the forces share the same line of action.
 Column Buckling Stress  The allowable buckling stress of a column.
 Concurrent Force  All of the forces act at the same point.
 Conservation Law  States that the total energy of an isolated system remains constant and its physical properties are conserved over time.
 Constant Acceleration  The constant rate in a straight line at which the velocity changes with respect to time.
 Constant Angular Acceleration  An object is the constant rate at which the angle velocity changes with respect to time.
 Coplannar Parallel Force  The forces can be in the same or opposite direction and are on the same plane.
 Cross Product Operator  The cross product of two vectors. It is a binary operation that takes two vectors as input and returns a third vector that is perpendicular to both of the input vectors.
 Cyclic Deflection  The repeated change in temperature or vibration.
 Cylinder Axial Stress  The longitudinal stress parallel to the axis along a cylinder or pipe having both ends closed due to internal pressure.
 Cylinder Hoop Stress  The circumference stress in a cylinder of pipe having both ends closed due to internal pressure.
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 Deceleration  The rate of change of velocity, this is the opposite of acceleration.

Deflection  The change in the position of something from zero or from its normal position.

Deformation  Measured by how much an object is deformed from its origional dimensions.

Deformation Coefficient  The force restricting the movement of an object that is sliding or rolling and one or both surfaces are relatively soft and deformed by the forces.
 Deformation Wear  A type of wear that occurs when two surfaces come into contact and undergo plastic deformation, resulting in material loss or surface damage.

Degradation  A deleterious change in the physical properties evidenced by impairment of these properties.
 Deionization  The process which removes soluble matter from water by by ion exchange using natural or synthetic resins.
 Density  The ratio of the amount of matter in an object compared to its volume.

Density of an Ideal Gas  Greatly affected by pressure.
 Density of Material due to Temperature 
 Design Pressure  Also known as working pressure. The normal pressure that a system operates at.
 Differential  The quantitative difference between two or more forces, pressure, time, etc.
 Diffusion  The spread of gases, liquids, or solids from areas of high concentration to areas of low concentration.
 Displacement  The change in position.

Displacement Power  The amount of power required to displace an object a certain distance over time with a known force.
 Distance  The dimension from one point to another point or the dimension from one end to the other end of an object.
 Doppler Effect  The increase (or decrease) in the frequency of sound, light, or other waves as the source and observer move toward (or away) each other.
 Drag Coefficient  A force that opposes an object as it moves through the air.
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 Efficiency  Expressed in percentage and always less than 100%.
 Elastic Deformation  The reversible and temporary change in shape or size of a material when subjected to external forces or loads within its elastic limit.
 Elastic Modulus  The ratio of the stress applied to a body or substance to the resulting strain within the elastic limits.
 Elastic Modulus of Concrete  Valid for normal weight concrete.

Elasticity  Measures the stiffness of an elastic material.
 Elongation  The increase in length to which a material is to be stretched prior to rupture.
 Elongation Percentage  The percentage of elongation at the fracture.
 Energy  Never created or destroyed, First Law of Thermodynamics, but it can be transferred from one object to another.
 Equilibrium  When all the net external forces that act upon an object are balanced.
 Escape Velocity  The minimum velocity required to leave a planet or moon or the minimum velocity to overcome the pull of gravity.
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 First Moment of Area  The measurement of a shape's area crosssection relative to an axis, located in space.
 First Moment of Inertia  The measurement of a shape's area crosssection relative to an axis, located in space.
 Flotation  A process similar to aeration in that gas (typically air) is induced or dissolved to aid in "floating" oil and suspended solids so they can be separated mechanically.
 Fluid Pressure at Depth  The pressure exerted on a fluid depends only on the depth of the fluid.
 Force Exerted by Contracting or Stretching a Material  Any strain exerted on a material causes an internal elastic stress.
 Fresh Air  Air taken from outdoors.
 Friction  The mechanical resistance to the relative movement of two surfaces.
 Friction Coefficient  The ratio between two contacting surfaces and the frictional force that resists the normal force of the object.
 Friction Loss  How much loss of flow through a pipe is due to the viscosity, the measure of the internal friction/resistance to the flow of a liquid near the surface of the pipe.
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 gforce  A force (force per unit mass) equal to one unit of gravity that is multiplied during a rapid change in direction or velocity.
 Gas Oil Ratio  When oil is brought to surface conditions it is usual for some gas to come out of solution. The ratio of a given volume of gas at standard pressure and temperature (STP) to a given volume of produced oil.

Graham's Law  The rate at which gases disperse is inversely proportional to the square root of their mass.
 Graham's Law of Effusion  The rate at which gases disperse is inversely proportional to the square root of their mass.
 Gravitation  A force pulling togeather all matter.
 Gravitational Acceleration  The force on an object caused only by gravity.
 Gravitational Field  A region of space where forces are exerted and affect anything that has mass.
 Gravitational Force  A force (force per unit mass) equal to one unit of gravity that is multiplied during a rapid change in direction or velocity.
 Gravitational Potential Energy  The energy stored in an object due to its height above the earth.

Gravitational Mass  Measured by comparing the force of gravity of an unknown mass to the force of gravity of a known mass.
 Gravity  A force pulling togeather all matter.

Gravity Scale  If a fluids API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks.
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 Impact Resistance  Ability to withstand mechanical blows or shock without damage seriously affecting the effectiveness of the material or system.
 Impact Strength  Resistance or mechanical energy absorbed by a material to such shocks as dropping and hard blows.

Impulse  The force applied to an object over time.
 Impulse Velocity  A change in momentum of an mass when a force is applied.

Impulse with Time  A change in momentum of an mass when a force is applied over time.
 Inertia  A property of matter that describes its resistance to a change in motion or state of rest.
 Initial Length  The length before linear thermal expansion.
 Initial Velocity  The starting point at which motion begins.
 Instantaneous Acceleration  The acceleration at a particular moment in time along its path.
 Instantaneous Angular Acceleration  The rate an object rotates in a circular path at a particular moment in time.
 Instantaneous Velocity  The change in time approaches 0, is the velocity at a particular moment in time along its path.
 Internal Mass  The mass of an object measured by its resistance to acceleration when a force is applied.
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 Kepler's Laws of Planetary Motion  Describe the motion of the planets in the solar system.
 Kinematics Equations  These equations are about objects in motion and their interrelationship.
 Kinematic Viscosity  The ratio of dynamic viscosity to density or the resistive flow of a fluid under the influance of gravity.
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Lateral Deflection  When an object (flex connector) is bent off it's centerline and both of it's ends are parallel to each other.
 Launch Velocity of a Projectile 
 Law of Actions and Reaction  For every action there is an equal and opposite reaction.
 Law of Conservation  States that the total energy of an isolated system remains constant and its physical properties are conserved over time.
 Law of Conservation of Angular Momentum  States the angular moment of a system of particles around a fixed point is conserved if there is no net external torque around that point.
 Law of Conservation of Electric Charge  States the sum of all the electric charges in any closed system is constant.

Law of Conservation of Energy  States that energy cannot be created or destroyed, but may be changed from one form to another. This means that the total energy in an isolated system remains constant over time.
 Law of Conservation of Linear Momentum  States if the net external force acting on a system of bodies is zero, then the momentum of the system remains constant.

The Law of Conservation of Mass  States that matter can neither be created or destroyed. You can mix, separate or rearrange, but the total amount of mass remains the same.
 Law of Conservation of Massenergy  States that the energy can change from one form to another, but it cannot be created or destroyed.
 Law of Conservation of Matter  States that the mass of an object or collection of objects never changes over time, even when the matter changes form.
 Law of Conservation of Mechanical Energy  States the total mecanical energy in a system remains constant as long as the only force acting are conservative forces.
 Law of Conservation of Momentum  States that momentum only moves from one place to another, since it is neither created or destroyed.
 Law of Inertia  A object at rest remains at rest and a object in motion continues to move at a constant velocity unless acted upon by an external force.
 Law of Resultant Force  The force that causes an object or mass to accelerate.
 Length  The dimension from one point to another point or the dimension from one end to the other end of an object.

Length Differential  The difference between an expanded or reduced length of an object.
 Linear Motion  A one direction motion on a one dimensional plane using acceleration, displacement, and velocity.
 Linear Strain  The deformation, stretched or compressed, of a material compared to its original length.
 Linear Velocity  The velocity of an object moving in a straight line along a circular path.
 Liquid  A specific volume and can hold any shape it is contained within.
 Linear Motion  An object is the amount of mass in motion.
 Localized Loss  Refers to the pressure drop or decrease that occurs at specific points or components within a fluid flow system.
 Longitudinal Strain  The deformation, stretched or compressed, of a material compared to its original length.
 Longitudinal Stress  The stress imposed on the long axis of any shape. It can be either a compressive or tensile stress.
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 Magnetic Energy  The potential energy stored in a magnetic field. The magnetic energy stored in an inductor is proportional to the square of the current flowing through it and the inductance of the inductor.
 Mass  The amount of matter an object has.
 Mass Diffusivity  A proportionality constant between the molar flux due to molecular diffusion and the gradient in the concentration of the species.
 Mass Flow Rate  The average velocity of a mass that passes by a point.
 Mass Transfer Coefficient  A porportional constant to the difference in the concentrations and the rate of mass transfer.
 Mean Free Path  The average distance that a object travels between collisions.
 Mechanical Energy  The sum of the change in kinetic energy and potential energy generating from the force of gravity, external forces or the movement released in machine movement.
 Mechanical Properties  Those properties that reveal the reaction, elastic or plastic, of a material to an applied stress, or that involved the relationship between stress and strain.
 Modulus of Rigidity  The ratio of the tangential force per unit area applied to a body or substance to the resulting tangential strain within the elastic limits.
 Modulus of Toughness  Quantifies toughness. The area under the stressstrain curve upto fracture point.

Molar Mass  The mass of a given compound equal to its molecular mass in gram.

Molar Mass of Gas  The mass in atomic mass units, of one mole of a substance.
 Molarity  The concentration of a solution (substance being dissolved).
 Molecular Coefficient  The force restricting the movement of an object that is sliding on an extremely smooth surface or where a fluid is involved.
 Moment  The tendency to cause a body to rotate around an axis.
 Moment of Inertia  Measures the resists or change an object has to rotational acceleration about an axis.
 Moment of Momentum  How much an object is rotating around a fixed point.
 Momentum  An object is the amount of mass in motion.
 Momentum Change in Velocity  When the velocity changes but the mass remains constant.
 Motion  The acceleration, displacement, or velocity of an object relative to a given frame of reference.
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 Net Positive or Negative Force  Two forces can add or subtract to the net force when the forces act on each other.
 Newton's First Law  A object at rest remains at rest and a object in motion continues to move at a constant velocity unless acted upon by an external force.
 Newton's Laws of Motion  These three laws show the relations between the forces acting on a body and the motion of the body.
 Newton's Law of Universal Gravitation  All objects in the universe exert a gravitational force of attraction on each other.
 Newton's Second Law  The force that causes an object or mass to accelerate.
 Newton's Third Law  For every action there is an equal and opposite reaction.
 Normal Force  Is always perpendicular to the surface it contacts and equal to the weight of the object. Unless there is another external force pushing the object into the contact surface there will be no normal force.
 Number Density  The number of items per unit volume.
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 Overall Efficiency  Measures the ratio of the output of actual power to the input of actual power.
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 Physical Properties  Those properties familiarly discussed in physics, for example, density, electrical conductivity, and thermal expansion coefficient, exclusive of those described under mechanical properties.
 Plasma  It is everywhere in the universe and the most common of all matter. Of all types of matter it is closest to a gas.
 Plastic Deformation  The permanent and nonreversible change in shape or size of a material when subjected to external forces or loads beyond its elastic limit.
 Poisson's Ratio  The elastic ratio between lateral strain and longitudinal strain.
 Polar Moment of Inertia  Defines the resistance of a crosssection to torsional deformation, due only to the shape of the crosssection.
 Potential Energy  The possessed energy by a body due to its relative position in a gravitational field.
 Pressure  The force exerted perpendicular to the surface of an object and is expressed as force per unit area.
 Pressure Differential  The pressure difference between two points of a system.
 Proof Stress  A specified stress to be applied to a member or structure to indicate its ability to withstand service loads.
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 Radius of Gyration  The distance from the axis of rotation to a point where the total mass of the body is supposed to be concentrated.
 Rate of Change in Acceleration  The time derivative of acceleration, the second derivative of velocity or the third derivative of position.
 Rate of Change in Velocity  The first derivative of velocity, the second derivative of position or the instantaneous change in velocity. In physics, it is known as acceleration.
 Relativistic Mass  The mass of a body which changes with the speed of the body as this speed approaches close to the speed of light.
 Resistance  The measure of the opposition to the flow of any physical quantity, not just electric current.
 Rest Mass  When the body is at rest and motionless, and is also relative to an observer moving or not moving.
 Resilience Modulus  The amount of energy a material can absorb and still return to its origional shape.

Rolling Coefficient  The combination of static, deformation and molecular coefficients of friction.
 Rolling Rersistance  Occurs when a resistance force is applied to a rolling wheel.
 Rotational Acceleration  The rate at which the angle velocity changes with respect to time.
 Rotational Inertia  Measures the resists or change an object has to rotational acceleration about an axis.
 Rotational Momentum  How much an object is rotating around a fixed point.
 Rotational Stiffness  The resist deformation of an object in response to an applied force.
 Rotational Work  Overcoming resistance for a distance by force and then adding torque.
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 Second Area Moment  The resistance of an object to bend around a certain axis of a area crosssection.
 Second Moment of Area  The resistance of an object to bend around a certain axis of a area crosssection.
 Service Factor  Used to reduce a strength value to obtain an engineering design stress.
 Shear Carriage  Bottom section of the shear that rises when a cut is made and catches the pieces of scrap. Located at the weld.
 Shear Crack  A diagonal, transgranular crack caused by shear stresses.
 Shear Force  The force acting perpendicular to the longitudinal xaxis. Also called axial force.
 Shear Modulus  The ratio of the tangential force per unit area applied to a body or substance to the resulting tangential strain within the elastic limits.
 Shear Modulus of Elasticity  The ratio of the tangential force per unit area applied to a body or substance to the resulting tangential strain within the elastic limits.
 Strain  Opposing forces acting parrallel to the crosssection of a body.
 Shear Strength  The stress requied to produce a fracture in the plane of ctosssection, the condition of loading being so much that the directions of force and of resistance are parallel and opposite although their paths are offset a specified minimum amount.
 Shear Stress  Tends to deform the material by breaking rather than stretching without changing the volume by restraining the object.
 Solid  Has particles that are compressed together in an orderly pattern.
 Specific Gravity  The density or ratio of any substance to another substance. It sometimes may be called just gravity or relative density.
 Specific Gravity of Gas  The ratio of the density of the gas to the density of air at a standard pressure and temperature.
 Specific Gravity of Soil  The mass of solids in the soil compared to the mass of water at the same volume.
 Specific Volume  A intensive variable whose physical quantity value does not depend on the amount of the substance for which it is measured.
 Specific Weight  The weight per unit volume of a substance.
 Specific Mass  The ratio of the amount of matter in an object compared to its volume.

Speed  The rate of change or distance with time.
 Speed of Light  A speed which remains constant irrespective of the speed of the source of the light or of the observer.

Speed of Sound  The distance traveled for a specific time through a medium from particle to particle.
 Stagnation Pressure  The pressure a fluid exerts when the velocity of the fluid is zero.
 Static Efficiency  Measure of an air mover's efficiency based on its air horsepower in terms of flow and static pressure vs. required shaft input power.
 Static Friction  The force that resists relative movement and keeps objects at rest.
 Static Pressure  The difference in air pressure between the suction side and pressure side of a blower.
 Statics  Concerns itself with forces when no change in momentun occurs.
 Stiffness  The resistance of the elastic deformation of an object that applies to both compression and tension.
 Stopping Distance  When a vehicle is moving at a certain velocity then has to come to a complete stop, the distance from applying the brakes to complete stop is the stopping distance.
 Strain  The deformation, stretched or compressed, of a material compared to its original length.
 Strain Energy  The energy stored in an elastic body of the material undergoing deformation.
 Stress  The force per unit area of crosssection.
 Surface Fatigue Wear  Repeated rolling or sliding contact, in which the shear stresses bring about microcracks, particles and form wear pits that destroy the surface.
 Surface Pressure  The lateral force per unit length applied on a line perperdicular to the force.
 Surface Tension  The energy or force at the surface of a liquid that holds it together.
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 Tangential Acceleration  How much the tangential velocity of a point at a radius changes with time.
 Tangential Velocity  The velocity at any point tangent to a rotating object.
 Tear Strength  Resistance of a material to tearing.
 Tension (Change in Dimension) 

Tension Strength  The capacity of a material to resist a force tending to stretch it.
 Terminal Velocity  When an object is falling under the influence of gravity but with no other influences.
 Test Time  A measurement to define a continuous series of events.
 Thermal Stress  The change in the temperature of the material that causes expansion or contraction.
 Thrust Force  A force that moves an object.
 Time  Measurement to define a continuous series of events.
 Torque Speed 

Torsion  The stress of twisting of an object due to applied torque.
 Torsion Constant for Circle Crosssection 
 Torsion Force  The force applied to the structural member or an object causing one end to twist with respect to the other end.
 Torsional Deflection  The twisting of an object around its axis or centerline.
 Toughness  The ability of a material to absorb considerable energy without fracturing.
 Translational Momentum  An object is the amount of mass in motion.

Trajectory of a Projectile  The curved path given an initial velocity and is acted on by gravity.
 Trajectory of a Projectile on a Hill 
 Turbidity  The cloudiness or haziness of a fluid caused by individual particles (suspended solids) that are generally invisible to the naked eye.
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 Ultimate Tensile Strength  The maximum stress a material can resist before it starts to elongate.
 Understressing  Applying a cyclic stress lower than the endurance limit.
 Uniform Strain  The strain occuring prior to the beginning of localization of strain.
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Vacuum  A contained space having little or no matter or a volume having a pressure lower than the outside atmospheric pressure.
 Vapor Density of Gas 
 Velocity  The rate of change or displacement with time.
 Velocity Differential  The average rate of change or displacement with time.
 Velocity Gradient  How the velocity of a fluid changes between parallel planes or different points within the fluid.
 Vibration Resistance  The property of a material to resist mechanical vibration without wearing away, settling or dusting.
 Volumetric Mass Density  The ratio of the amount of matter in an object compared to its volume.
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 Wear  Wear is brought about from the gradual removal of particles due to contacting surfaces in motion, usually sliding, generally as a result of mechanical action.
 Weight  Weight is a force on an object accelerated by gravity.
 Weight Density  The basic difference between density and weight is that weight is a measure of the amount of matter in an object, whereas density measures the amount of matter in a unit volume.
 Weight Force  The force of gravity or the weight.
 Wind Chill Factor  An index of the air temperature and the wind velocity.
 Wind Energy  The kinetic energy of air in motion.
 Work Done by Gas  The product of force and distance but for gas work is pressure and the volume during the change in volume.

Work Energy Theorem  The change in the kinetic energy of an object is equal to the net work done on the object.
 Working Pressure  The normal pressure that a system operates at. Also known as design pressure.
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 Yield Point  The point where an elastic material is permanent change in length with no extra load force.
 Yield Ratio  The ratio of yield strength to ultimate tensile strength.
 Yield Strength  The minimum stress that leads to permanent deformation of the material.
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