# Shared Flashcard Set

## Details

Physics for Life Sciences
University of Guelph PHYS*1080
221
Physics
12/08/2015

Term
 Absolute pressure
Definition
 Total pressure Hydrostatic pressure at the surface of a fluid. Gauge pressure + 1 atm.
Term
 Acceleration
Definition
 The rate of change in velocity. A vector.
Term
 Acceleration of gravity (g)
Definition
 Near the surface of the Earth, g = 9.8 m/s2.
Term
 Allometric
Definition
 Not isometric. The structure of different animals are allometric. Causes deviations in sometric scaling laws.
Term
 Allometry
Definition
 The study of relationship of body size to other characteristics: shape, anatomy, behaviour, metabolisms, breathing, heart rate, cruising speed.
Term
 Aneurysm
Definition
 The walls of arteries become weakened with age or disease, to the point that at peak blood pressure, the blood vessel balloons or bursts. Can be fatal.
Term
 Angular acceleration (α)
Definition
 The change in angular velocity of a rotating object over time. All points in a rigid body have equal angular acceleration in a rotation.
Term
 Angular displacement (Δθ)
Definition
 The change in angle in a rotation. Proportional to arc length. All points in a rigid body have equal angular displacement in the rotation.
Term
 Angular momentum (L)
Definition
 The rotational analog of momentum. A vector.
Term
 Angular velocity (ω)
Definition
 The angular displacement of a rotating object over time. Has units of radians per second, or revolutions per minute. All points in a rigid body have equal angular velocity in a rotation.
Term
 Arc length (Δs)
Definition
 The distance moved by a point in a rotation. Proportional to the angular displacement.
Term
 Archimides' Principle
Definition
 Any object placed in fluid experiences a buoyant force equal in magnitude to the weight of the fluid that object displaces.
Term
 Atmospheres (atm)
Definition
 A unit of pressure 1 atm = 101.3 kPa
Term
 Average speed
Definition
 The distance travelled divided by elapsed time.
Term
 Average speed of flow (v)
Definition
 The average speed of all streamlines in streamline flow.
Term
 Average velocity
Definition
 The rate of change of position. A vector. Negative or positive. Not to be confused with average speed.
Term
 Bar
Definition
 A unit of pressure 1 bar = 105 Pa
Term
 Barometric formula
Definition
 P/P0 = e-mg(h1 - h0)(kBT)
Term
 Barometric pressure
Definition
 Compares atmospheric pressure between two altitudes.
Term
 Bernoulli's effect
Definition
 A fluid has a lower pressure when it is flowing faster. Responsible for the phnomenon of lifting of wings, and curveballs in baseball.
Term
 Bernoulli's equaton
Definition
 P + ½pv2 + pgh = contant Used for ideal fluids with no viscosity, and no pressure drops across the tube. Used when there is a change in tube radius or elevation.
Term
 Biomechanics
Definition
 The mechanics of living things, including deformable solids, and fluids
Term
 Blackbodies
Definition
 Objects which are perfect radiators or absorbers of all wavelengths within the spectral region of interest.
Term
 Blood pressure
Definition
 Systolic/Diastolic Measured in mmHg.
Term
 Boltzmann's contang (kB)
Definition
 R/NA = 1.381 x 10-23 J/K
Term
 Boltzmann's equation
Definition
 Applies to all kinds of energy states that molecules have. Identical to the modified barometric formula. N2/N1 = e-(E2 - E1)/kBT = e-ΔE/kBT
Term
 Bolus flow
Definition
 Occurs in capillaries. Erythrocytes block the capillary, trapping small amounts of plasma between them, which have rapid flow in the centre that deflects towards the walls of the capillary. Facilitates rapid movement of nutrients and wastes across the capillary walls.
Term
 Breaking stress
Definition
 The level of stress at the fracture point.
Term
 Brittle
Definition
 A material which has an extensibility close to the elastic limit.
Term
 Bubble pressure
Definition
 A factor of 2 is used for gas bubbles in liquid. A factor of 4 is used for gas-filled liquid bubles in gas.
Term
 Buoyant force
Definition
 An upward force which causes any object in fluid to seem weightless.
Term
 Calorie (C)
Definition
 The unit food energy is measured in. The amount of thermal energy required to raise the temperature of one gram of water by 1ºC. 1 C = 4.186 J
Term
 Capillaries
Definition
 Small vessels of the circulatory system. Have a diameter of 5 - 6 μm.
Term
 Canonical distribution function
Definition
 A function for the probability that a molecule in a system has energy of E or equivalent. PE = (e-(E/kBT))/(Σe-(Ei/kBT))
Term
 Cellulose
Definition
 The major structural component of plants. A polymeric sugar.
Term
 Centre of mass (cm)
Definition
 The point at which force of gravity can be assumed to act on an extended object. The lower the centre of mass, the more stable an object is.
Term
 Centrifugal force
Definition
 Does not actually exist. It seems as though objects are "pushed" away from the centre of the circle, but this is due to the constantly changing direction of motion of an object in circular motion. This illusion is due to having a non-inertial frame of reference.
Term
 Centrifuge
Definition
 A device used to separate substances in a solution or suspension according to their densities. Samples are rotated very rapidly in a circle: increasing centripetal acceleration.
Term
 Centripetal acceleration (ac)
Definition
 The non-zero acceleratoin of an object in uniform circular motion. The direction is towards the centre of the circle.
Term
 Centripetal force (Fc)
Definition
 The mass of an object in uniform motion, times its centripetal acceleration. Always directed towards the centre of the circle. Not a real force, and is never included in a free body diagram.
Term
 cmH2O
Definition
 A unit of pressure used to measure lung pressure 1 cmH2O = 98 Pa
Term
 Coefficient of static friction (μs)
Definition
 Depends on the nature and composition of both contacting surfaces. Rough or sticky surfaces increase the value.
Term
 Coefficeint of viscosity (η)
Definition
 Depends on the composition of the fluid and other parameters such as temperature and pressure.
Term
 Collagen
Definition
 A major structural component of ligaments, bones, muscles, skin, and blood vessles. A fibrous protein. Has helical molecular arrangements.
Term
 Completely inelastic collision
Definition
 A collision where the objects stick together after colliding.
Term
 Composite material
Definition
 Materials assembled from two or more chemical species. Most structural components of biological systems are composite materials.
Term
 Compression
Definition
 When the force of tension is pushing into the object, rather than pulling it.
Term
 Compressive strain
Definition
 Tensile strain when an object is under compression.
Term
 Compressive stress
Definition
 Tensile stress when an object is under compression.
Term
 Condensed matter
Definition
 Liquids and solids. Arise when attractive forces between molecules are relatively strong.
Term
 Conduction
Definition
 Transfer of heat through direct physical contact between two objects at different temperatures.
Term
 Conservation of angular momentum
Definition
 Angular momentum is independent of time.
Term
 Conservation of energy
Definition
 Energy cannot be created or destroyed, only transformed from one type to another.
Term
 Conservation of momentum
Definition
 Momentum is conserved when objects collide.
Term
 Conservative force
Definition
 The work done by these force depends only on the coordinates of the points, not on the path followed by the object. Includs gravitational, electrical, and elastic forces.
Term
 Contract angle (θ)
Definition
 A measure of the curvature of the liquid-vapour interface of a droplet of liquid.
Term
 Continuity Equation
Definition
 Q = Av
Term
 Convection
Definition
 A process by which the physical movement of a fluid transfers heat from one location to another.
Term
 Density
Definition
 The mass per unit of volume. Affects hydrostatic pressure.
Term
 Diffusion
Definition
 Brownian motion Particle which are very small and/or have very similar density as their suspending medium are distributed evenly in the medium by thermal energy. Displacement as a result of thermally driven velocities. Can occur in 1D, 2D, or 3D.
Term
 Diffusion coefficient (D)
Definition
 Its units are m2/s
Term
 Dilatant
Definition
 A non-Newtonian fluid. Fluids where viscosity increases with stress. Example: corn starch in water, Silly Putty.
Term
 Displacement
Definition
 The change in position of the object during its motion. Negative or positive. Not to be confused with distance traveled.
Term
 Ductile
Definition
 A material which has an extensibility which is much greater than the elastic limit.
Term
 Dynamic equilibrium
Definition
 The object is moving, but velocity is constant. Kinetic friction is used.
Term
 Dynamic light scattering
Definition
 A method for determining the diffusion coefficeint using laser light scattering.
Term
 Dynamics
Definition
 The relationship of motion to the forces that cause it. Force and acceleration are considered constant.
Term
 Elastic collision
Definition
 Total kinetic energy is conserved.
Term
 Elastic hysteresis
Definition
 When resiliance of a material is less than 100%, and follows a different strain curve when stress is decreased than when stress is increased.
Term
 Elasitc limit
Definition
 Yield point The highest level of strain within the elastic range.
Term
 Elastic range
Definition
 The range of strain between the proportional limit and elastic limit. If the stress is removed, the material will relax into its original length. All deformation is reversible.
Term
 Elasticity
Definition
 The ability of a solid material to undergo deformation without breaking or becoming permanently deformed.
Term
 Elastin
Definition
 "Natural rubber" A major structural component of ligaments. A fibrous proteins. Large extensibility.
Term
 Energy
Definition
 Includes gravitational, electrical, chemical, nuclear, and mechanical energy.
Term
 Equation of continuity
Definition
 A1v1 = A2v2
Term
 Equilibrium
Definition
 When net force is zero. The object is at rest, or in uniform motion.
Term
 Erytrocytes
Definition
 Red blood cells Have a diameter of 8 μm.
Term
 Extensibility
Definition
 The level of strain at the fracture point for a tensile stress.
Term
 Fick's Law
Definition
 The flux of particles (J) is proportional to the concentration gradient. J = -D(ΔC / Δx)
Term
 Fluids
Definition
 Liquids and gasses. Never reach an equilibrium; continue to deform when stress is applied.
Term
 Food energy
Definition
 Energy that enables animals to do muscular work. Stored in chemical bonds and is released when food is digested. Measured in calories.
Term
 Force
Definition
 Vectors that act on objects to move them.
Term
 Fracture point
Definition
 Breaking point The level of strain at which the material fractures.
Term
 Frame of reference
Definition
 A coordinate system relative to the observer, which may be in motion in relation to the ground.
Term
 Free fall
Definition
 All bodies in free fall have the same acceleration. This was discovered by Galileo.
Term
 Friction
Definition
 A force which opposes the relative sliding motion of two objects whose surfaces are in contact.
Term
 Galilean equations
Definition
 Equations that may be used when an objects has constant acceleraton.
Term
 Gauge pressure
Definition
 Relative pressure
Term
 Gaussian distribution
Definition
 Normal distribution Distributions that depend on the Gaussian function. Forms a bell curve. The most probale, and average velocity is zero. Changing temperature widens the width of the bell curve.
Term
 Gaussian function
Definition
 Named after Johann Karl Friedrich Gauss. N2/N1 = e-(mvx2/2kBT)
Term
 Geometric centre
Definition
 If the mass of the object is distributed uniformly, it is the same as the centre of mass.
Term
 Gravitational potential energy (U)
Definition
 Mass*height*g
Term
 Heat of condensation
Definition
 The heat of transformation to change a gas into a liquid. Has the same magnitude as heat of vaporization.
Term
 Heat of fusion (Lf)
Definition
 The heat of transformation to change a solid into a liquid.
Term
 Heat of solidification
Definition
 The heat of transformation to change a liquid into a solid. Has the same magnitude as heat of fusion.
Term
 Heat of transformation
Definition
 Heat needed to be added or removed to change the phase of a substance with no change in temperature. Measured in J/kg. Includes heat of fusion, vaporization, condensation, and solidification.
Term
 Heat of vaporization (Lv)
Definition
 The heat of transformation to change a liquid into a gas.
Term
 Hooke's Law
Definition
 When stress is sufficiently small, it is proportional to strain.
Term
 Hyaline membrane disease
Definition
 A disease that affects premature infants. The lipoprotein surfactant in the lungs is absent. Molecules have high surcace tension, and alveoli collapse.
Term
 Hyaluronic acid
Definition
 A polysaccharide that controls the viscosity of synovial fluid.
Term
 Hydrostatic pressure
Definition
 Pressure in a fluid that depends on depth.
Term
 Hypertonic
Definition
 A solution which causes a decrease in volume of a cell placed in solution.
Term
 Hypotonic
Definition
 A solution which causes an increase in volume of a cell placed in the solution.
Term
 Ideal fluid
Definition
 Has no frictional forces. Viscosity is zero.
Term
 Ideal Gas Law
Definition
 PV = nRT R = 8.315 J/mol*K
Term
 Inelastic collision
Definition
 Total kinetic energy after the collision is less than before the collision. Some energy is lost to heat and sound.
Term
 Inertia
Definition
 An object's resistance to changes in motion. Proportional to the mass of the object.
Term
 Instantaneous speed
Definition
 The magnitude of instantaneous velocity.
Term
 Instantaneous velocity
Definition
 The velocity at any specific instant in time. A vector. Positive or negative. For a curved path, instantaneous velocity is a tangent of the curve.
Term
 Isometric
Definition
 Has the same geometry, and different size. Used to suggest trends in living organisms: upper limits of size, function of organs and organelles, strength, speed, age, intelligence. Two isometric objects with a linear dimension twice that of the other, has 4 time as much surface area and 8 times as much volume.
Term
 Isotonic
Definition
 A solution which causes no change in volume of a cell when placed in the solution.
Term
 Johann Karl Friedrich Gauss
Definition
 1777 - 1855 A German mathematician. Wrote the Gaussian function.
Term
 Joule (J)
Definition
 The SI unit for work.
Term
 Kinetic friction
Definition
 Friction that resists a change in velocity of an object, based on the coefficient of kinetic friction.
Term
 Kinetic theory
Definition
 The quantitative analysis of translational movement of molecules.
Term
 Linear contributions
Definition
 Translational contributions to motion.
Term
 Linear regime
Definition
 When deformations are small, Y is constant.
Term
 Lumen
Definition
 Cell contents.
Term
 Lung pressure
Definition
 MIP/MEP Measured in cmH2O
Term
 Manometer
Definition
 A device which measures pressure. Commonly uses mercury, water, or oil.
Term
 Maxwell
Definition
 Realized that collisions between pollen grains were what caused the chaotic motion Brown observed.
Term
 Mean square velocity
Definition
 A parameter of interest for Gaussian distributions. Increases with temperature.
Term
 Mechanical energy
Definition
 The sum of kinetic and gravitational potential energy.
Term
 Mechanics
Definition
 The branch of physics concerned with the relationship between the motion of an object and the forces acting on it.
Term
 Meteorology
Definition
 Pressure is measured in bars.
Term
 Microfluidics
Definition
 The study of fluid flow in small channels. Devices can be made to perform many functions: uniform emulsions, encapsulation, DNA/cell screening, and many applications.
Term
 mmHg
Definition
 A unit of pressure used to measure blood pressure. 1 mmHg = 132.8 Pa
Term
 Moment arm
Definition
 The perpendicular distance of the torque force from the pivot.
Term
 Moment of inertia (I)
Definition
 The limit of the sum of masses of each particle, times r2 of an object. SI unit is km*m2. Depends on the location of the axis of rotation.
Term
 Multisegmented body
Definition
 Capable of changing body shape, thereby changing the moment of inertia value when the axis of rotation is unchanged. Angular velocity changes. The energy for the increase in kinetic energy is from the effort put into changing shape.
Term
 Net force
Definition
 Resultant force The sum of all forces on an objet. When net force is greater than zero, the object accelerates.
Term
 Net weight
Definition
 Apparent weight The effective weight of an object in fluid Vg(ρ - ρl)
Term
 Newton (N)
Definition
 The SI unit of force. The magnitude of force that produces an acceleration of 1 m/s2 on a 1 kg object 1 N = 1 kg*m/s2
Term
 Newton's First Law
Definition
 A body remains at rest or in uniform motion in a straight line, unless it is acted on by a non-zero force.
Term
 Newton's Law of Cooling
Definition
 A hot body with no internal source of heat will cool off. Applies only for small changes in temperature. Can apply to large changes if the air is constantly moved past the cooling object. T = TS + (TO - TS)e-κt
Term
 Newton's Law of Universal Gravitation
Definition
 Every particle of matter in the universe attracts every other particle with a force of FG, directed along the line between them. The magnitude of this force is proportional to the masses of the particles, and inversely proprotional to the distance between them. This law can be extended to apply to objects, as long as they have spherically symmetric mass distribution.
Term
 Newton's Second Law
Definition
 If a force acting on an object is not zero, the object accelerates in the direction of the force. The magnitude of acceleration is proportional to the magnitude of the force, and inversely proportional to the mass of the object.
Term
 Newton's Third Law
Definition
 For every force, there is an equal and opposite reaction force. It does not matter which of the two forces is considered the action and which is considered the reaction.
Term
 Newtonian fluid
Definition
 A fluid that obeys the equation η = FΔy/AΔy Includes water, alcohol, and liquid metals. Viscosity depends on temperature.
Term
 Non-conservative forces
Definition
 The work done by these forces depends on the path followed by an object. Includes friction.
Term
 Non-equilibrium dynamics
Definition
 F = ma is tru in at least one direction. Kinetic friction is used.
Term
 Non-inertial frame of reference
Definition
 Causes the illusion of centrifugal "force".
Term
 Non-Newtonian fluid
Definition
 A fluid that does not obey the equaion η = FΔy/AΔy. Viscosity depends on: flow speed or shear stress. Includes thixotropic materials, synovial fluid, shear thinning materials, dilatant materials, and viscoelastic materials.
Term
 Non-uniform motion
Definition
 Occurs when velocity changes over time.
Term
 Not wet fluids
Definition
 Have an obtuse contact angle.
Term
 Nuchal ligament
Definition
 The ligament in a cow's neck which holds the head of the cow up with tension, acting along with the spinal cord.
Term
 Osmolality (Cos)
Definition
 Osmoles of solute per unit of mass of solvent. Units are moles/kg. Used for solutions in high concentrations, and eliminates temperature dependence.
Term
 Osmolarity
Definition
 The sum of the molarities of all solutes in a solution, measured in Osmoles (Os).
Term
 Osmosis
Definition
 The movement of solvent molecules across a semi-permeable membrane which prevents solute molecules from passing. Due to osmotic pressure.
Term
 Osmotic pressure (Π)
Definition
 Causes osmosis.
Term
 Osmotically active
Definition
 Any molecule that cannot cross a biological membrane. Large molecules, charged organic molecules, and inorganic ions.
Term
 Osmotially inactive
Definition
 Any molecule that can cross a biological membrane. Includes water, oxygen, nitrogen, carbon dioxide, small neutral molecules such as short chain alcohols and glycerol.
Term
 Perrin
Definition
 In 1890, demonstrated the distribution of potential energy of particles suspended in liquid, using a suspension of gamboge.
Term
 Pivot
Definition
 Fulcrum The fixed axis about which an object is free to rotate.
Term
 Plasma
Definition
 The fluid in which red blood cells are suspended.
Term
 Plastic range
Definition
 The range of strain after the elastic limit. The material does not return to its original length when stress is removed. The object undergoes permanent deformation.
Term
 Poise
Definition
 A unit of velocity, named after Poiseuillie. 1 poise = 1 x 10-1 N*s/m2
Term
 Poiseuille's Law
Definition
 Q = πr4(P1 - P2)/8ηL Used when a fluid is viscous and the tube does not change radius.
Term
 Power (P)
Definition
 The rate of change of energy. Measured in Watts.
Term
 Pressure
Definition
 Magnitude of normal force per unit area. The same in evrey direction. Fluids exert pressure on any immersed surface. Units include atm, mmHg, bars, and cmH2O.
Term
Definition
 ΔP/L
Term
 Projectile motion
Definition
 Two-dimensional motion with constant acceleration. Acceleration is broken into its x and y components.
Term
 Proportional limit
Definition
 The level of strain after which Hooke's Law no longer applies.
Term
 Pulsatile flow
Definition
 Streamline flow which is not continuous and constant. The triangular area under the curve of Q vs. t gives volume of flow per beat. Example: heart-driven blood flow.
Term
Definition
 Transmission of heat energy through electromagnetic waves. May travel through a vacuum or transparent medium.
Term
 Random walk
Definition
 The process of diffusion of particles.
Term
 Rate of heat loss (H)
Definition
 Heat generated depends on mass, and heat loss depends on surface area.
Term
 Relative velocity
Definition
 The velocity of an object in relation to an observer which may also be in motion.
Term
 Resilience
Definition
 The closeness of the strain curve for increasing and decreasing stress. 100% resilience produces an identical strain curve for  both.
Term
 Reynold's number (Re)
Definition
 ρvavD/η Turbulent flow usually occurs after a disturbance when this number exceeds 2000 (1000 if radius is used in calculations).
Term
 Rigid body
Definition
 A body that does not change size or shape.
Term
 Robert Brown
Definition
 In 1827, observed that pollen grains in solution displayed random chaotic motion. Observed that the motion of the pollen grains could be influenced by temperature.
Term
 Root mean square displacement
Definition
 xrms = vx,rmst
Term
 Root mean square velocity (rms)
Definition
 Must be a positive number vx,rms = √v2x
Term
 Rotational contribution
Definition
 A contribution to motion.
Term
 Rotational equilibrium
Definition
 Either in a state of rest, or in motion with constant angular velocity. The sum of torques exerted by the forces about any point is zero.
Term
 Rotational motion
Definition
 Can occur in non-point objects. Different ponits of the body move in concentric circles about a stationary axis through the body.
Term
 Scaling
Definition
 A type of dimensional analysis. Used to study the effects of changes in size among otherwise similar organisms on body structure and function. Describes how different parts of a system change size as the whole system changes size. Example: the relative widths of the leg bones of land animals of different sizes.
Term
 Shear modulus (G)
Definition
 Analogous to Young's modulus, but for shear. Usually has a value 0.3 - 0.5 that of the Young's modulus.
Term
 Shear straing (εs)
Definition
 Strain resultant from shear strss. Layers of molecules are forced to slide past each other.
Term
 Shear stress (σs)
Definition
 A pair of equal and opposite forces are applied tangentially to opposite surfaces of a body.
Term
 Shear thinning material
Definition
 A non-Newtonian fluid. Becomes less viscous with more shear.
Term
 Solute
Definition
 A substance dissolved in a solvent.
Term
 Solvent
Definition
 A substance in which a solute is dissolved.
Term
 Specific gravity (s.g.)
Definition
 The density of a substance relative to water.
Term
 Specific heat capacity (C)
Definition
 Specific heat A characteristic of a substance and its state. Measured in J/kg*K.
Term
 Sphygmomanometer
Definition
 A device which measures blood pressure.
Term
 Static equilibrium
Definition
 The object is not moving. Static friction is used.
Term
 Static friction force
Definition
 Exactly balanced friction so that the object remains at rest. Adjusts in response to applied force.
Term
 Statistical thermodynamics
Definition
 The canonical distribution function is a fundamental equation of this discipline.
Term
 Stefan's Law
Definition
 I = σT4
Term
 Stokes-Einstein equation
Definition
 DF = kBT
Term
 Streamline flow
Definition
 Laminar flow Fluid moves along smooth lines. Velocity of flow is near zero  near the walls, and fastest in the centre.
Term
 Sublimation
Definition
 Change from a solid to a gas. Occurs under certain conditions.
Term
 Surface tension (γ)
Definition
 Associated with the surface energy of liquids. Causes circular bubbles, transpiration of plants, bugs walking on water, and enables us to breathe. Measured by holding a wire in place over a fluid and pulling upwards. Units are N/m.
Term
 Synovial fluid
Definition
 Fluid which fills the cavities of synovial joints in mammals, such as the knee. Viscosity decreases as the stress and velocity gradient increase, allowing for smooth joint operation. Problems lead to arthritis. Similar to blood plasma, but has less protein and contains hyaluronic acid.
Term
 Tangential acceleration (at)
Definition
 The instantaneous angular acceleration of a rotating object in the direction of the tangent of the circle.
Term
 Tensile strain (ε)
Definition
 Strain The fractional chance in length of an object under tension.
Term
 Tensile strength
Definition
 The level of strain at the fracture point for a tensile stress.
Term
 Tensile stress (σ)
Definition
 Stress The ratio of magnitude of the force of tension to the cross sectional area. SI units N/m2.
Term
 Tension
Definition
 The simiplest type of elastic behaviour. Stretching of an object when both its ends are pulled.
Term
 Terminal velocity
Definition
 The maximum velocity of an object in freefall. Small objects reach terminal velocity very quickly.
Term
 Thermal energy
Definition
 kBT An term. Change in thermal energy can cause motion.
Term
 Thixotropic
Definition
 A non-Newtonian fluid. Substances that are fluid when they are in motion, and solid when still. Example: wet sand, non-splatter paint.
Term
 Torque (τ)
Definition
 Moment The effectiveness of a force at causing a rotation. The force times the distance from the pivot. Positive torque produces a counter-clockwise motion. Negative torques produce a clockwise motion.
Term
 Torsion
Definition
 When shear force is applied tangentially to the circumference at one end of a cylindrical rod while the other end is held fixed. The rod will twist around its axis.
Term
 Turbulence
Definition
 When the flow rate exceeds a certain level, it becomes noisy and inefficient. The fluid swirls rather than flows in streamline. Generates heat, and vibrates pipes and joints. Can be suppressed by very smooth vessel walls. Cannot use Bernoulli's euqation or Poiseuille's Law.
Term
 U-tube manometer
Definition
 Used to measure the pressure differences between two gas chambers.
Term
 Uniform circular motion
Definition
 The motion of an object moving at a constant speed in a circular path. Speed is constant, but direction is constantly changing. Velocity is tangent to the circle.
Term
 UNiform motion
Definition
 Occurs at a constant velocity, a constant speed, in a straight line. Plots of x vs. t will be a straight line. Instantaneous velocity equals average velocity.
Term
Definition
 Δv/Δy
Term
 Viscoelastic
Definition
 A non-Newtonian fluid. Materials which have different elastic properties depending on the rate at which stress is applied.
Term
 Viscosity
Definition
 The internal friction that occurs in fluids when there is flow. Most gasses and liquids have very low viscocity. Units are N*s/m2.
Term
 Volume flow rate (Q)
Definition
 Av Flow rate Units are m3/s
Term
 Watt (W)
Definition
 The SI unit for power 1 W = 1 J/s
Term
 Weight
Definition
 The downward force of an object when the Earth's gravity is the only force acting on it.
Term
 Wein's Law
Definition
 Gives the wavelength of the maximum spectral emittance (λm).
Term
 Wet fluids
Definition
 Have an acute contact angle.
Term
 Work
Definition
 Force times distance. Measured in Joules.
Term
 Work-energy theorem
Definition
 The total work done on an object by all forces acting on it. Equals the change in the object's kinetic energy. A consequence of Newton's second law.
Term
 Young's modulus (Y)
Definition
 The proportionality constant between stress and strain in Hooke's Law. Different for different materials. A measure of the strength or stiffness of a material. SI units are N/m2.
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