test 4- Final Flashcards Preview

biomechanics > test 4- Final > Flashcards

Flashcards in test 4- Final Deck (27)
Loading flashcards...
1
Q

stresses and strains on the body

A

internal and material properties of biological materials (compression, tension, bending, torsion, shear)

2
Q

external forces that act on the body affect the movements of..

A

the entire boys and also impose loads that affect the internal structures

3
Q

internal structures of the body

A

cartilage, tendons; ligaments, bones, and muscle

4
Q

understanding of the mechanical properties of the internal structures is important for…

A

preventing injury and evaluating the causes of injury

5
Q

stress

A

the external forces that act on the body are resisted by internal forces and cause deformation of the body

6
Q

the amount of deformation produced is related to…

A

the stress caused by the forces and the material that is loaded

7
Q

Do the 2 rubber bands stretch as much as the single rubber band did under the same force?

A

the deformation (or stretch) of the 2 rubber bands was not as large as that of the single rubber band unless you exerted twice as much force (the stress of the 1 rubber band is 2x as large as the stress of the 2 rubber bands)

8
Q

mechanical stress

A

the internal force divided by the cross-sectional area of the surface on which internal force acts (stress may vary within an object and is associated with a specific internal surface)

9
Q

three principal stresses

A

tension, compression, shear

10
Q

SI Unit for Stress

A

N/m^2 (Pascals)

11
Q

static equilibrium

A

if the rubber band is held still in a stretched position; ignoring weight, the pulling force at each end must be equal

12
Q

the force of stress represents…

A

the resultant of all the individual intermolecular bond forces that act across the surface of the imaginary cut and hold the rubber band together

13
Q

the cross sectional area (stress)

A

is at the imaginary cut plane (analysis plane) used to define the stress at this plane

14
Q

stress=

A

internal force/CSA of the internal surface

15
Q

E=

A

change in length/ original length

16
Q

axial stresses (normal or longitudinal stresses)

A

tension and compression; acts perpendicular (or normal) to the analysis plane

17
Q

transverse stress

A

shear

18
Q

Tensile Stress

A

(rubber band example) is the axial or normal stress that occurs at the analysis plane as a result of a force or load that tends to pull apart the molecules bonding the object together at that plane

19
Q

which anatomical structures are longer in one dimension than in the other 2? (tension)

A

long bones, muscles, tendons, ligaments

20
Q

stress in such structures is typically analyzed by (tension)

A

considering analysis planes that cut through the structure perpendicular to its longest dimension

21
Q

the stresses that act perpendicular to the analysis planes (this the long acid of the structure are called

A

axial, normal, or longitudinal stresses

22
Q

axial loading (tension)

A

a loading situation in which the forces act in the direction of the long axis of the bone (if cut perpendicular stress could be determined in the bone)

23
Q

if the force tends to pull the bone apart and stress acts away from the analysis plane the stress is…

A

tensile stress

24
Q

if the cross sectional area changes as you move distally along its length what else changes?

A

the stress changes/varies (inversely)

25
Q

an object tends to deform by stretching or elongating in the direction of the…

A

external loads

26
Q

for most materials, this elongation is directly proportional to the…

A

magnitude of the stress

27
Q

in humans, very large tensile loads may…

A

sprain or rupture ligaments and tendons, tear muscles and cartilage, and fracture bones