Chapter 9 Flashcards
What is kinematics?
Spatial and timing characteristics of motion of the human body without reference to forces causing the motion
What is kinetics?
The internal or external forces that cause movement
What is quantitative analysis?
Measuring
What is qualitative analysis?
Visual or aural analyses of performance
What are internal forces?
Forces generated by muscle pulling on bone via their tendons
And
Bone-on-bone forces exerted across joint surfaces
What are external forces?
Forces acting upon the body from without (gravity)
What is biomechanics?
Science examining internal and external forces acting on the body and the effects produced by these forces
What are the 3 models of human motion analysis?
Particle model
Stick figure model
Rigid body segment model
What is linear motion?
When all parts of the body move the same distance , in the same direction
What is another term used for linear movement?
Translation
Define translation
Movement of the body as a unit without individual segment parts of the body moving in relation to one another
What is angular motion, or rotation?
When a body moves on a circular path and in the same direction
What is the axis of rotation?
The line about which bodies rotate
What is general motion?
Combination of linear and angular motion
What is mass?
The measure of how much matter an object has
What is inertia?
The property of objects to stay in motion or at rest unless acted upon by an outside force
What are the 4 questions of kinematics?
How far
How long
How fast
How consistent was the motion
What is Newton’s 1st law of motion?
Inertia: objects will not change their state of motion unless acted upon by an unbalanced external force
Define torque, or moment of force.
When a force causes angular motion
What is angular kinetics?
The rotation about an axis of rotation and the control of these rotations
What components comprise lever systems?
An axis of rotation (fulcrum)
Lever attached to fulcrum
What is the force arm?
Distance from axis to where the force is applied
What is the resistance arm (RA)?
Distance from the axis to where the resistance is applied
What is the formula for torque?
Force arm (FA) x force
How many types of levers are there?
3
What is Newton’s second law of motion?
Acceleration: for linear movements, acceleration a body experiences is directly proportional to the force causing it and takes places in the same direction as the force
What is the formula for acceleration?
F = m x a
What is the Magnus effect?
The net difference in pressure on opposite sides of a rotating body generating a force that changes the bodies direction or flight path (topspin, curveball)
What is stability?
Measure of the easy or difficulty with which equilibrium can be disturbed
What factors effect stability?
Base of support size (bigger support = greater stability
Body mass (more mass, harder to move)
Center of gravity (lower center of gravity = more stability
Increase horizontal distance between the intersection of the vertical line from the center of mass intersecting with the base of support and outside edge of the base of support
What 4 steps are used to teach via qualitative analysis?
Preparation
Observation
Evaluation
Error correction
The fluid through which a body moves generates what?
Surface and profile drag
What is profile drag?
The air turbulence produced by an objects shape and size as it moves through air
What is surface drag? (Skin friction)
Caused by surface toughness as a body moves through air
Particle models are used for what?
When the object is airborne or in flight
When is the stick figure model used?
Used when athletes are in contact with the ground or other earthbound objects
When is the rigid body segment model used?
When a sophisticated 3D is used to represent each body segment
