Chapter 3 Flashcards
Study of physical actions of forces
Mechanics
Study of mechanics as it relates to the functional and anatomical analysis of biological systems
Biomechanics
used to increase the applied force (effort) in performing a task
Machine
Machine provide mechanical advantage : What are they?
Can apply a relatively small force to move a greater resistance
Move one point of an object a small distance to result in a large amount of movement of another point of the object
Can be calculated using which two formulas”
MA=Res/force
MA= Length of force arm/ resistance of force arm
machines fucntion to :
- balance multiple forces
- enhance force
- enhance range of motion and speed of movement
- alter resulting direction of applied force
In the human body, arrangement of musculoskeletal system provides 3 types:
levers
wheels/axels
pulleys
Most common form of simple machine in the human body
Lever
Rigid bar that turns about an axis of rotation (fulcrum)
lever
Lever has another name also known as….
Fulcrum
Lever rotates as a result of ….. being applied to it, causing its movement against a …..
force; resistance
Resistance is in the middle
Second class lever
Axis is in the middle
First class lever
force is in the middle
Third class lever
What is movement doing in the first class lever?
Movement is balanced
Produce speed and range of motion when axis is close to force
siccors ; first class lever
Produce force motion when axis is close to resistance
Crow bar: first class lever
Agonist produces the…..whereas the antagonist supplies the …
force; resistance `
Large resistance can be moved by a relatively small
force
second class lever
examples: tiptoe in the body and wheelbarrow and nuttcracker
second class lever
Produce speed and range of motion movements
third class lever
examples of third class lever.
requries a great deal of force to move a small resisitance
paddling and shoveling
what is the most common third class lever in the human body?
Biceps brachi; flexing elbow
example : Biceps Brachii flexing elbow Axis= Force= Resistance= Results in moving forearm
Elbow joint
applied by biceps brachii at its insertion on radius
Resistance=weight of arm, additional objects
Results in moving forearm
Moment of force, or the turning effect of an eccentric force
torque
force applied off center
Applied force not in line with object’s center of gravity
Causes rotation
Contracting muscles apply eccentric forces to the bone on which it attaches, causing the bone to rotate about the axis (joint)
eccentric force
Distance between the axis and the point of resistance application
resistance arm
What is the lever equation?
force x force arm = resistance x resistance arm
Know how to perfrom math calc
refer to ppt
Human leverage system is built for …
speed and range of motion at the expense of force
A single…..changes effective direction of force application
pulley
What law is thisA body in motion tends to remain in motion at the same speed in a straight line unless acted on by a force
newton law of interia
A body in….. tends to remain in ….. at the same …. in a straight line unless acted on by a ….
motion; motion; speed; force.
Muscles produce force to …
start, stop, accelerate, deecerlate, and change the direction of moton
the rate of change in velocity
accelration
A change in the acceleration of a body occurs in the same direction as the force that caused it
newton law of accelation
The change in acceleration is directly proportional to the …. causing it and inversely proportional to the …..
force ; mass of the body
For every action there is an opposite and equal reaction
Newton law of reaction
state of zero acceleration
No change in speed or direction of the body
Static or dynamic
equiliibrium
ability to control equilibrium
balance
resistance to change in the body’s equilibrium
Maximize stability to achieve balance
stability
point at which all of the body’s mass and weight is equally balanced
center of gravity
where is the center of gravity located ?
inersection of 3 cardinal planes
What are the main source of force that allows us to change movments of body ?
msucles
if the axis is near the force… then the mechanail advatnage is said to be ?
less than 1
if the axis is near the resistance…then the mechanical advatnage is said to be..
greater than 1
force applied to wheel
mroe than 1
force applied to axle
less than `
1
