(1) Biomechanics Basics and Terminology-- Physics Flashcards
What is the study of FORCES and their effects?
mechanics
What is the branch of mechanics that deals with the geometry of the MOTION OF OBJECTS (including displacement, acceleration, velocity)?
Kinematics
What is the study of RELATIONSHIPS b/w the FORCE system acting on the body and the changes it produces in BODY MOTION?
kinetics
What uses the principle of mechanics for SOLVING PROBLEMS related to structure and function of biologic and physiologic systems?
Biomechanics
Do Scalars or Vectors contain magnitude only?
Scalars
What are the three aspects that pertain to Scalars?
Distance, speed, mass
magnitude only
Do Scalars or Vectors contain magnitude AND direction?
vectors
What are the six aspects that pertain to Vectors?
displacement, velocity, acceleration, weight, momentum, force
Is distance a Scalar or Vector quantity?
Scalar
Is displacement a Scalar or Vector quantity?
Vector
What is “how much ground an object has covered during its motion”?
distance
What is “how far out of place an object is” and is the overall change in position?
displacement
Are distance and displacement the same or different when moving in one direction in a straight line?
they are equal
Are distance and displacement the same or different when travel is not in a straight line?
different
Is speed a scalar or vector quantity?
scalar
What is “how fast an object is moving” and is the rate in which an object covers distance?
speed
Is velocity a scalar or vector quantity?
vector
What is “the rate at which an object changes its position”?
velocity
What is distance/time?
What is displacement/time?
speed
velocity
Is speed ignorant or aware of direction?
ignorant (can be instantaneous OR average)
Is velocity ignorant or aware of direction?
aware (DIRECTION MATTERS!!)
What does HVLA stand for?
High VELOCITY, Low Amplitude
For a HVLA chiropractic adjustment, describe the rate of displacement. Describe the amplitude.
Rate of displacement = RAPID
Amplitude = short depth
What is the rate at which an object changes its velocity?
acceleration
What is the equation for acceleration?
change in velocity/ time
Is acceleration a scalar or vector quantity?
vector
What two things does the direction of the acceleration vector depend on?
- whether object is speeding up or slowing down
- whether object is moving in + or - direction
Is mass a scalar or vector quantity?
scalar
What is the mass of an object referring to? What is it measured in?
the amount of matter that is contained by the object–> how much stuff is present in the object
g or kg
Is weight a scalar or vector quantity?
vector quantity
What units is weight measured in and how is “weight” created?
N
is the force of gravity acting upon that object
the force with which gravity (Earth or any planet) pulls upon the stuff
What is the conversion of Newtons to kilograms to pounds?
10 Newtons = 1 kilogram = 2.2 pounds
What happens to the gravitational attraction as the centers of the two bodies are moved farther apart?
it decreases (and vice versa)
When does gravitational attraction b/w two bodies change?
when the distance b/w their centers is changed
Is momentum a scalar or vector quantity?
vector
What is a term for “mass in motion” and the quantity of motion an object posses?
momentum
What is the equation for momentum?
mass x velocity
p = m x v
What is the relationship b/w momentum and mass and velocity?
momentum has a direct relationship with mass and velocity
- is mass doubles; so does momentum
- if velocity quadruples; so does momentum
What is the action (push or pull) upon a body causing it to deform or move? What is this measured in?
Force; measured in Newtons (N)
Is force a scalar or vector quantity?
vector
What is the required amount of force to give a 1kg mass an acceleration of 1 m/s^2?
one Newton
What is the equation for FORCE?
mass x acceleration
mass = quantity of matter that makes up a sample acceleration = change in velocity over a unit of time
What is Newtons First Law of Motion called?
the Law of Inertia
What is the resistance to having its state of motion changed by application of a force?
intertia
What is Newton’s First Law of motion state?
an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force
What is Newton’s Second Law of Motion called? How it is defined?
Law of Force and Acceleration
the acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object
Which of Newton’s Laws is the Thompson Technique an example of?
Newton’s Second Law of Motion–> aka Law of Force and Acceleration
What is Newton’s Third Law of Motion?
Law of Action and Rection
for every action, there is an equal and opposite reaction
“think pairs”
T/F. Every action force is met with an equal and opposite reaction force, and every action produces an equal and opposite reaction.
FALSE— yes, every ACTION FORCE is met with an equal and opposite REACTION FORCE–but.. every ACTION does not produce an equal and opposite REACTION
What is the force that keeps a girl in place when shooting a basketball and which of Newton’s Law is this?
friction; Third Law of Motion (Law of Action and Reaction)
What is the intensity of force perpendicular to the surface on which it acts?
Normal Stress
think of like “gravity” for us as chiro’s
What is the intensity of force parallel to the surface on which it acts?
Shear stress
When does Static Friction exist?
when two contacting surfaces are not currently sliding relative to each other but do possess the potential for movement
What is the Coefficient of Static Friction for and what does it represent?
the ratio required to initiate a sliding motion b/w two bodies
represents the difficulty of sliding any given surface over another b/c of their textures (think about “interlocking,” grooves, scratches)
What will a Static Friction Coefficient of 0.0 tell us? What about 1.0?
- 0 = friction less
1. 0 = maximum friction
What is the Static Friction Coefficient for synovial joints? What is it for Kinetic Friction?
.01
.003
What is the term for friction in cases when the two surfaces are already sliding relative to each other?
Kinetic Friction; aka dynamic friction
think of “bumping” into another, NOT interlocking
What happens to friction force as soon as the applied parallel force exceeds static friction force and the object begins to slide?
friction force actually decreases
What is the amount of magnitude of applied force acting over a give area? What is the equation for this? What is it measured in?
Pressure
P = F/A
pascals (Pa)
1 Pa = 1 N/m^2
What is the performed when an object is displaced by the application of a force?
Work
What is being performed when we do a chiropractic adjustment?
work!!!
What is the equation for work and what is it measured in?
Force (N) x Distance (m)
joule (J)
1 J = 1 N x m
Is work positive or negative?
can be BOTH
T/F. When a lot of physical effort is involved and the object isn’t displaced, Mechanical work is still performed.
FALSE– no matter how much physical effort was involved on the part of the person, technically no Mechanical work was performed if the object wasn’t displaced
What is the term for the energy an object possesses due to motion? What is this measured in?
kinetic energy
joules
What effect do changes in velocity have on kinetic energy?
have large effects (due to being squared in the equation–> KE = 1/2 mv^2
What is the kinetic energy of an object that isn’t moving?
0; is has NO KE
What will cause the kinetic energy to change of an object?
when there is a net force doing work on an object
What is term for the path of motion around a fixed axis and therefore in a circular path?
Angular Motion
What is the term for time rate of change of angular position of a rotating body?
Angular velocity
degrees or radians per unit of time
What is the term for the time rate of change of angular velocity of a rotating body?
Angular acceleration
What is the term for the point about which a body rotates?
Axis of Rotation
What is the term for the perpendicular distance from an axis of rotation to a line along which a force acts?
Lever arm— aka force arm or moment arm
What is the term for the product of force and lever arm, the tendency of an eccentric force to rotate an object around an axis?
Torque
What does a lever system consist of?
rigid or semi-rigid object (lever) that is capable of rotating about an axis (fulcrum)
Describe the relationship of the fulcrum, load, and effort for a Type 1 Lever. Give examples.
fulcrum is b/w the effort and load/resistance
Ex: see-saw, claw hammer, opening paint can, scissors
Describe the relationship of the fulcrum, load, and effort for a Type 2 Lever. Give examples.
load/resistance is b/w the fulcrum and the effort
Ex: stapler, wheelbarrow, nut cracker, car door
Describe the relationship of the fulcrum, load, and effort for a Type 3 Lever. Give examples.
effort is b/w the fulcrum and load/resistance
Ex: fishing rod, broom, tweezers, tongs
What is the most common type of Lever?
Type 3 Lever (effort is b/w the fulcrum and load/resistance)
What is the ratio of the motive force (effort) to a given resistive force called?
Mechanical Advantage
Moment arm (M) = force x lever arm distance
What is the equation for Mechanical Advantage?
MA = M-m / M-r
What will a larger number for Mechanical Advantage tell us?
the more leverage the given lever system provides
If the Mechanical Advantage is greater than 1, what is our mechanical advantage in?
force
If our Mechanical Advantage is less than 1, what is our MA in?
in speed and ROM
What if our Mechanical Advantage is 1.00? What does this mean?
the fulcrum is directly in the middle of the lever and NEITHER force has an advantage
If we have a Mechanical Advantage of 100, what does this tell us? What is the advantage? What is the disadvantage?
effort is further than load from the fulcrum = lever operated at a MA
advantage = force disadvantage = speed and distance
(Ex: jacking up a car)
If we have a Mechanical Advantage of .5, what does this tell us? What is the advantage? What is the disadvantage?
effort nearer than the load to the fulcrum = lever operates as a mechanical disadvantage
advantage = speed and distance disadvantage = force (takes more effort)
Ex: shoveling
If the load is close to the fulcrum and effort is applied far from the fulcrum, describe the effort and distance relationship and the load and distance relationship.
What is this lever said to operate at?
SMALL effort exerted over relatively LARGE distance–> moves a LARGE load over a SMALL distance
= lever said to operate at a MA
What is the advantage and disadvantage to a Type 3 lever?
Advantage = ROM
Disadvantage = Effort required
What is the advantage and disadvantage to a Type 2 Lever?
Advantage = Effort required
Disadvantage = ROM
What is the advantage and disadvantage to a Type 1 Lever where the effort is closer to the fulcrum?
Advantage = ROM
Disadvantage = Effort Required
What is the advantage and disadvantage to a Type 1 Lever where the load is closer to the fulcrum?
Advantage = Effort required
Disadvantage = ROM
What type of Lever is are the biceps brachi?
Class 3 Lever
What type of Lever are the hamstrings curling up the leg?
Class 3 Lever
What type of Lever are the lumbar paraspinal muscles an example of?
Class 1 Lever
