Study guide chapter 3 Flashcards
mechanics
study of physical actions of forces
statics
constant state of motion either movement or none
lever
rigid bar that turns about an axis of rotation or fulcrum
dynamics
study of systems in motion with acceleration
force
product of mass times acceleration
torque
movement of force
FA VS RA
perpendicular distance between force application and axis VS distance of axis point to resistance application
pullyes
functional compounds to change effective direction of force
linear motion
angular motion
curvilinear motion
reticular motion
motion along line
rotation around an axis
motion along curved line
motion along a straight line
velocity
includes direction and describes rate of displacement
law of acceleration
change in acceleration of body occurs in the same directions as force that caused it
static friction
kinetic friction
rolling friction
-amount of friction from movements that haven’t moved
- amount of friction between 2 moving objects
- resistance to an object rolling across a surface
momentum and impulse
quantity of motion
product of force and time
static VS dynamic equillibrium
body is at rest no movement VS all applied internal forces acting on moving body are in balance
4 ways machines function
-balance multiple forces
-enhance force in attempt to reduce total force needed to move an object
- enhance ROM/speed of movemnt
-alter resulting direction of applied force
3 types of machines
levers, wheel and axels, pulleys
Class 1 lever
axis in middle
force on left going down
resistance on right going down
EX; head balanced on neck flexing and extending
class 3 lever
force in middle going up
resistance going down on left
axis on right
EX; biceps in elbow flexion
class 2 lever
resistance in middle going down
axis on left
force going up on right
EX; planter flexion
in body what is wheel and axle used for
enhance ROM and speed of movement
what general factors can enhance equilibrium and maximize stability to help achieve balance
lower center of gravity, increasing base of support, distribute weight evenly
what forced cause mechanical loads
internal /external
what generates active internal forces VS passive internal forces in body
muscles VS tendons, connective tissue, ligaments, joints
what generates external forces
gravity, inertia, direct contact
6 types of force that may cause excessive tissue deformation
tension - stretch
compression - compressing from top an bottom
shear- force from one on each side
bending - bending
torsion- spinning
combines torsion/ compression
to prevent injury or damage form tissue deformation what does body do
used absorb enegery from both ex and int forces
parts of body represent following lever parts
bars= bones
axis= joint
force= muscles
