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Law of Inertia
A body will maintain a state of rest or constant velocity unless acted on by an external force that changes the state. TERM 2
Law of Acceleration
DEFINITION 2 A force applied to a body causes an acceleration of that body of a magnitude proportional to the force, in the direction of the force, and inversely proportional to the bodys mass. F = ma TERM 3
Law of Reaction
DEFINITION 3 For every action, there is an equal and opposite reaction. When one body exerts a force on a second, the second body exerts a reaction force that is equal in magnitude and opposite in direction on the first body. TERM 4
Law of Gravitation
DEFINITION 4 All bodies are attracted to one another with a force proportional to the product of their masses and inversely proportional to the square of the distance between them. TERM 5
Turbulent Flow
DEFINITION 5 Sufficient high velocity Layers of the fluid near the surface of the object mix
Laminar Flow
Sufficient low velocity Smooth layers of fluid molecules flowing parallel to one another TERM 7
Archimedes principle
DEFINITION 7 The buoyant force acting on a body is equal to the weight of the fluid displaced by the body Center of volume Point around which the bodys volume is equally distributed Flotation TERM 8
Buoyancy
DEFINITION 8 Flotation of the human body Body density Orientation while floating CG is generally inferior to the center of volume CG and CV torque TERM 9
Skin Friction
DEFINITION 9 Resistance derived from friction between adjacent layers of fluid near a body moving through fluid Boundary layer Increases proportionally with increases in relative fluid velocity Major drag when flow is laminar TERM 10
Form Drag
DEFINITION 10 Occurs when boundary layer is primarily turbulent Major contributor to overall drag Creates a pressure differential
Topspin
Ball drops more rapidly and tends to rebound low and fast.Traps a relatively large boundary layer of air with it as it spins TERM 17
Sidespin
DEFINITION 17 Follows a curved path in the direction of the spin throughout its flight pathIf axis of rotation is perfectally vertical, all of the Magnus effect occurs in the horizontal plane TERM 18
Backspin
DEFINITION 18 Creates an upward directed Magnus Force that increases flight time and flight distanceAxis of the spin is perpendicular to the direction of the relative fluid velocity TERM 19
Theoretical Square law
DEFINITION 19 Drag increaes approximately with the square of velocity when relative velocity is low. Ex. cyclists double their speed and other factors remain constant, the drag force opposing them increase fourfold. TERM 20
Archimedes
Principle
DEFINITION 20 A water polo ball with a volume of 0.2 m*3 is completely submerged in water at 20C, the buoyant force acting on the ball is equal to the ball's volume multiplied by the specific weight of water at 20C
Laminar Flow
Flow charactarized by smooth, parallel layers of fluid TERM 22
Turbulent flow
DEFINITION 22 flow characterized by mixing of adjacent fluid layers. Nonlaminar The nature of fluid flow surrounding an object can dramastically affect the fluid forces exerted on the object. TERM 23
Angular Acceleration
DEFINITION 23 Rate of change in an angular velocityChange in angular velocity occuring over a given time. TERM 24
Angular Acceleration
DEFINITION 24 a=(w2-w1)/(t2-t1)W1=angular velocity at an initial point in timeW2=represents angular velocity at a second or final point in timeT1=times at which velocity was assessed T2=times at which velocity was assessed TERM 25
Tangential Acceleration
DEFINITION 25 Component of acceleration of a body in angular motion directed along a tangent to the path of motion; represents change in linear speed. Measures the rate of change in the linear speedof the ball
Angular Displacement
change in the angular position or orientation of a line segmentEx. bicep curls when the forearm returns to its original position, the elbow is zero at this TERM 32
Angular Displacement
DEFINITION 32 A backswing in golf is negative due to the club going clockwiseA swing in golf is positive due to the club going counterclockwise TERM 33
Absolute angle
DEFINITION 33 Angular orientaion of a body segments with respect to a fixed line of reference. Should consistenly be measured in the same direction from a single reference-either horizontal or vertical. TERM 34
Relative angle
DEFINITION 34 angle at a joint formed between the longitudial axes of adjacent body segmentsShould be consistently be measured on the same side of a given pointThe straight, fully extended position at a joint is regarded as 0 TERM 35
Instant center of
rotation
DEFINITION 35 Precisely located center of rotation at a joint at a given instant in timeEx. the knee during knee extension
Goniometer
Used to measure joint angles TERM 37
Law of Acceleration
DEFINITION 37 Ex a defensive football player running down the field is blocked by an oppsoing player.The velocity of the defensive player following contact is a function of the player's original direction and speed and the direction and magnitude of the force exerted by the offensive player. TERM 38
Law of Inertia
DEFINITION 38 Ex. A skater gliding on ice will continue gliding with the same speed and in the same direction TERM 39
Law of Reaction
DEFINITION 39 A person leans with a hand against a rigid wall, the wall pushes back on the hand with a force that is equal and oppsite to that exerted by the hand on the wall TERM 40
Kinetic energy
DEFINITION 40 A body possesess this only when in motion. =1/2mv*
Center of Mass
Associated with every body is a unique point around which the body's mass is equally distributed in all directions TERM 47
Stability
DEFINITION 47 Resistnace to disruption of equilibrium.Mechanically as resistance to both linear and angular acceleration.Ex. offensive lineman blocking for his QB TERM 48
Relative Velocity
DEFINITION 48 Velocity of a body with respect to the velocity of something else, such as the surrounding fluid.Ex. a sailboat traveling with a tailwind with a current going against the boat. TERM 49
Buoyancy
DEFINITION 49 A fluid force that always acts vertically upward. TERM 50
Skin friction
DEFINITION 50 Resistance derived from friction between adjacent layers of fluid near a body moving through the fluid.
Form Drag
resistance created by a pressure differential between the lead and rear sides of a body moving through a fluid. TERM 52
Form drag
DEFINITION 52 This dominates when the boundary layer of fluid molecules next to the surface of the moving body is primarily turbulent TERM 53
Wave Drag
DEFINITION 53 Resistance created by the generation of waves at the interface between two different fluids, such as air and water. Ex. a swimmer swimming in open water and air causing drag TERM 54
Bernoulli principle
DEFINITION 54 An expression of the inverse relationship between relative velocity and relative pressure in a fluid flow. Regions of relative high-velocity fluid flow are associated with regions of relative low pressure and vice versa. TERM 55
Lift
DEFINITION 55 Force acting on a body in a fluid in a direction perpendicular to the fluid flow.
Isometric
Describing a contraction involving no change in muscle length TERM 62
Momentum
DEFINITION 62 Quantity of motion that an object possesses Linear momentum M = mv Static object Collision of objects TERM 63
Coefficiant of
restitution
DEFINITION 63 Number that serves as an index of elasticity for colliding bodies TERM 64
Potential Energy
DEFINITION 64 Energy by virtue ofa body's position or configuration, calculated as the product of weight and height. TERM 65
Force Couple
DEFINITION 65 nPair of equal, oppositely directed forces that act on opposite sides of an axis of motion to produce torque nTorque to turn from the ballet fifth position
Nautilus Resistance Equiptment
Machine designed to match the changing torque generating capability of a muscle group throughout the range of motion at a joint. TERM 67
Isokinetic Resistance Equiptment
DEFINITION 67 Machine designed so that an individual applies force to a lever arm that rotates at a constant angular velocity.
