chapter 1 Flashcards
biomechanics is the study of
forces and their effect on living systems
force
push or pull exerted by one object onto another
force pairs are ___ in size but act in ____ direction on each object
equal, opposite
force unit
N
magnitude
size of the push or pull
direction of force
line of action
force point of application
where the push or pull is applied on the object
a vector quantity requires describing
magnitude and direction
force is represented graphically with an arrow:
length of the arrow represents
magnitude
force is represented graphically with an arrow:
arrowhead indicates
direction
force is represented graphically with an arrow:
shaft of the arrow indicates
line of application
internal force
pair of forces that act within the object or system
human internal forces
muscle and bone
tensile force
pulling/tension
compressive force
squeeze, push / compression
external force
acts on an object or system through interaction with environment
contact force
objects touching each other
non contact force
objects not touching each other
gravitational force
weight of the object
weight unit
N
gravitational acceleration
9.81m/s^2 downward
reaction forces
contact forces
each force acts separately on one of the objects
normal contact force
perpendicular to the two objects in contact
parallel contact force
parallel to contacting surfaces of two objects
friction force
parallel contact force
opposes motion or sliding between the surfaces
friction
opposes sliding or motion between objects in contact
friction results from
interaction between surface molecules
static friction
two surfaces not moving on each other
max friction before object starts to slide
limiting friction
dynamic friction
two surfaces moving on each other
dynamic friction AKA
sliding/kinetic friction
there is a balance to how much friction is good when we are doing ___ movements
dynamic
coefficient of friction
mu (u)
normal contact force letter
R
net force
sum of all external forces acting on one object
in force composition what must be accounted for
direction
colinear force
one or more external forces with the same line of action
concurrent forces
forces are not colinear but act through the same point
what is used to calculate concurrent force
pythagorean theorem/trigonometry
static equilibrium
body is not accelerating, forces are in equilibrium
