Biomechanics Module 5-7
What is the mass moment of inertia?
A rigid body's resistance to rotational motion
What best describes the center of mass (COM)? Balance point of a motionless body All the mass can be considered to be concerned around this point Translational motion can be describe at this point all of the above
All of the above
To obtain the least pressure Apply a large force spread over a large area apply a large force spread over a small area apply a small force over a large area apply a small force spread over a small area
Apply a small force over a large area
The principle or law used to describe lift is called?
Bernoulli's principle
From the center of rotation of a segment, which point is most proximal?
Center of mass (COM)
Which component of bone is primarily responsible for its tensile strength?
Collagen
The golgi tendon reflex action protects the contracting muscle by activating the muscle. T or F
False
The maximum amount of torque a muscle is able to produce about a joint is independent of the angle at the joint. T or F
False
How does a biomechanist generally find these body segment parameters?
Finds percentages in a table then does a simple calculation based on the individual
Which shape is most conducive to optimizing lift?
Foil
Identify the true statement: -Increasing the magnitude of a force acting on a surface area increases the amount of stress acting on the surface -decreasing the magnitude of a force acting on a surface area increases the amount of stress acting on the surface -both a and b are true -neither a nor b i true
Increasing the magnitude of a force acting on a surface area increases the amount of stress acting on the surface
Which of the following is an example of a gliding joint? -Humeroulnar joint -Proximal radioulnar joint -Glenohumeral joint -Intercarpal joint
Intercarpal joint
Which is not a method for measuring and estimating body segment parameters? Cadaver studies Laser measuring of photographs Mathematical modeling Kinematic techniques
Laser measuring of photographs
In which conditions would air resistance effects be more significant?
Low altitude venue on a cool day
Which can be used to properly describe laminar flow?
Parallel layers and reduce drag
What is anthropometry concerned with?
Physical characteristics and inertial properties
What reflex initiated during the backswing is critical in enhancing performance of a forehand drive in tennis?
Stretch
When applying rigid body mechanics to the study of human beings, which assumption is made?
The body does not deform by bending, stretching, or compressing
The tension-generating capability of a muscle is affected by: -the cross sectional area of the muscle -the arrangement of the muscle around a joint -both a and b -neither a nor b
The cross sectional area of the muscle
As relative velocity increases, the fluid forces acting on an object increase linearly: T or F
True
The size of the force produced in a whole muscle contraction can be controlled by: -altering the number of active motor units -altering the rate of stimulation -a & b -none of the above
a & b
A single motor neuron and all the muscle fibers with which it synapses define
a motor unit
The force applied by muscle is
a pull
The term muscle fiber refers to
a single muscle cell
articular cartilage covers
all bone surfaces at articulations
The vertical force that always acts vertically upward is
buoyancy
the more dense type of bone is called
cortical
The complete ossification of the epiphyseal cartilage in most long bones occurs:
during puberty
When a stretched material returns to its original shaped, it is called plastic refractive stiff elastic
elastic
When an object or material is axially loaded in tension with forces pulling at the ends, the object tends to: -stay the same length -refract -shorten in the direction of the external load -elongate in the direction of the external load
elongate in the direction of the external load
When a muscle contracts, it pulls with
equal force on each attachment
Stress is defined as the
force per unit area
Mobility, or the ease of movement through a range of motion, can be affected by all of the following except: -friction -hydration levels -muscles around the joint -damage to the synovial membrane
hydration levels
The unique distinguishing characteristic of muscle is
its ability to develop tension
Which body segment parameter is described using the variable I?
mass moment of inertia
When a muscle is stretched quickly, the resulting stretch reflex causes the
muscle to contract
The fundamental unit of the nervous system is the
neuron
During a concentric muscular contraction, the muscle does -positive work -muscle does no work -torque opposes the joint action -none of the above
positive work
Which body segment parameter is described using the variable k?
radius of gyration
The research on the tension length relationship of muscles indicates that a muscle is capable of generating maximal force when the muscle is:
slightly longer than resting length
The type of the join that allows for the greatest range of motion is called
synovial
Which stress is caused by a pull on the body acted upon?
tensile
The concept that explains how a spinning baseball changes direction is called
the Magnus effect
The ratio of stress of strain, the slope of the stress strain curve, is called
the elastic modulus
The muscle spindle detects
the stretch of a muscle or its relative changes in length