Classical Mechanics

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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

Classical mechanics Glossary


  • 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 Deflection Length  -
  • 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 cross-section.
  • 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 x-axis.  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.




  • 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 forcespressuretime, 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.


  • 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.











  • Overall Efficiency  -  Measures the ratio of the output of actual power to the input of actual power.


  • 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 non-reversible 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 cross-section to torsional deformation, due only to the shape of the cross-section.
  • Potential Energy  -  The possessed energy by a body due to its relative position in a gravitational field.
  • Power  -  The rate of doing work or the rate of using energy per unit time.
  • Power Velocity  -
  • 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.




  • Second Area Moment  -  The resistance of an object to bend around a certain axis of a area cross-section.
  • Second Moment of Area  -  The resistance of an object to bend around a certain axis of a area cross-section.
  • 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 x-axis.  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 cross-section of a body.
  • Shear Strength  -  The stress requied to produce a fracture in the plane of ctoss-section, 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 cross-section.
  • 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.



  • 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.



  • 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.




Piping Designer Logo Slide 1

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Impulse-Momentum Theorem
Abrasion Resistance
Absolute Roughness

Tags: Physics