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