# Shared Flashcard Set

Biomechanics
Quiz 2
44
Physiology
10/11/2011

## Additional Physiology Flashcards

Term
 what is acceleration an effect of?
Definition
 a FORCE
Term
 What is another name for Newton's 1st law of motion, and what does it state?
Definition
 "The Law of Inertia" it states a body @rest, will stay @rest, and a body in motion, will stay in motion, unless a NET force acts on body
Term
 what is inertia?
Definition
 a property of a body to resist a change (acceleration) in it's state of motion (change in it's velocity)
Term
 so in order to change an object's motion, what must be overcome?
Definition
 the object's inertia
Term
 what is mass?
Definition
 quantity of matter (stuff) of which a body is composed, a direct measure of a body's resistance to change linear motion, it's inertia.
Term
 What is Newton's 2nd law?
Definition
 "sum of the forces" and it is E(Sum)F = maunit: Newton
Term
 what direction is acceleration in when a gymnast is falling?
Definition
 in the same direction as the net force, in this case downwards
Term
 what are the characteristics of a force?
Definition
 it is a vector. so it has direction, magnitude, AND a point of application.
Term
 what are kinetics concerned with?
Definition
 they are concered with the CAUSES of motion
Term
 what is another name for Newton's 3rd law and what does it state?
Definition
 "the law of action-reaction" Every force has an equal and opposite force.-where you find a force, you will find 2 interacting bodies (both contact and noncontact).-Forces are always in pairs equal in magnitude, but opposite in direction
Term
 What are some implications of Newton's 3rd law?
Definition
 you must draw (2) systems/objects."action-reaction": these forces happen simultaneously, NOT sequentially
Term
 what is kinetics concerned with?
Definition
 the causes of motion
Term
 what does the gymnast and the footballer symbolize to us?
Definition
 that we must have knowledge of all three characteristics of a force to completely understand that a net force will have on an object's motion
Term
 what kinematic quantity allows us to measure the change in state of motion of an object?
Definition
 acceleration
Term
 what type of acceleration is the body's mass?
Definition
 linear acceleration because "a" is in the equation for newton's second law, not alpha
Term
 newton's 3rd law deals with how many systems?
Definition
 two
Term
 newton's second law deals with how many systems?
Definition
 1 system
Term
 what are examples of contact forces?
Definition
 ground reaction force, joint reaction force, friction, elastic force, muscle force, etc.
Term
 what is the GRF?
Definition
 ground reaction force is the reaction force provided by the surface upon which one is moving.
Term
 what are characteristics of GRF?
Definition
 it is a vector so it can be resolved into its components. it changes in magnitude, direction, and point of application during the period an individual is in contact with the surface
Term
 Fx is also referred to as? for a GRF
Definition
 mediolateral
Term
 Fy is also know as? and is parallel or perpendicular to motion?
Definition
 anteriorposterior, and is parallel to motion because you look at running in a sagittal plane
Term
 Where does the GRF act?
Definition
 it acts at the center of mass of the total body
Term
 what is the formula for vertical motion?
Definition
 (sum)F = m(body)*a(CoM)so... (GRFv - W) = m(body)*a(CoM)
Term
 If GRFv = W ... a = ?If GRFv < W ... a = ?If GRFv > W ... a = ?
Definition
 If GRFv = W ... a = no net force, no acceleration in CoMIf GRFv < W ... a = (-)If GRFv > W ... a = (+)
Term
 what type of force is friction and what does it oppose?
Definition
 it is a resistive force and it opposes RELATIVE motion
Term
 if you push on a chair and it doesn't move is there still friction? is friction force a constant?
Definition
 yes, external force is trying to move it. and no friction is not constant, there is a limiting value of friction.
Term
 how can we manipulate limiting value of friction?
Definition
 we can alter the max value of Flim by increasing Flim through football gloves, shoes, wax
Term
 F(lim) =
Definition
 F(lim) = u * R
Term
 give an example when we want friction? when we don't want friction?
Definition
 want: running, driving, walkingdon't want: skiing, moving furniture
Term
 F(slide) =
Definition
 F(friction) that is oppose the motion of the sliding object
Term
 what are the two states of sliding friction?
Definition
 static: no sliding occurs, pushing force is EXACTLY matched by the friction force.kinetic state: sliding occurs; pushing force exceeds F(lim)
Term
 what factors influence F(lim)
Definition
 1. the force pressing the two surfaces together - normal reaction force (R)****2. the nature of the two surfaces (u)
Term
 Rolling Friction or (RR) is produced when...
Definition
 one surface rolls over another. primarily it is due to a deformation of the surfaces in contact
Term
 is RR big or small? more or less than sliding friction? and what are three factors that influence RR?
Definition
 RR is small, usually less than sliding friction, and hardness of surface, force pushing surfaces together, and diameter of the rolling object
Term
 what is a definition of pressure and formula?
Definition
 force applied over an area vs. a concentrated point, and P = force / area unit: N/m^2 = pascal
Term
 force does not change between lying down vs. standing, rather ____ changes
Definition
 area
Term
 why is the concept of pressure important?
Definition
 important concept related to safety and injury protection, impact situations, the goal is to spread the force over as large an area of contact as possibel
Term
 how do crocs, a diabetic shoe, work?
Definition
 they take pressure away from the metatarsal heads
Term
 what is the difference in running barefoot versus with shoes?
Definition
 the pressure is extremely high barefoot
Term
 what were the results of caserotti et al.?
Definition
 jump height is higher in men, and higher power during concentric phase due to velocity component (not force)
Term
 explanations?
Definition
 women and fiber type, the had a reduced max response execution speed, and lower recovery from falls
Term
 what is the stretch shorten cycle?
Definition
 an eccentric muscle contraction followed immediadetly by a concentric muscle contraction
Term
 CMJ > SJ why?
Definition
 greater range of motion, more cross-bridges, more coordinate, longer time period, elastic energy stored in tendonJOINT MOMENTS ARE HIGHER in CMJ
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