EQUILIBRIUM OF RIGID BODIES
Fy O Free Body Diagram
E Fa o
EMO 0
LOADINGS
if distributed loadings made upof D I splitinto simpler
shapes
way was
I
I
, SIMPLE TRUSSES
jointare noncollinear
force directions onthat
no faceapplied to thatjoint
all loadings applied atjoints
1
2 members
joined by smooth pins s
ve 3unknownforces applied to thejointof which 2 are
collinear
the3rdone notcollinear is me zeroforce
ve member should merebe no applied face on that
joint
ii
CASE A CASE B
method of joints method of sections
if entire nss is in
equilibrium
if entire miss is
section of moss is as well
in equilibrium
see choosing what to section
joint is as well o
ty o
x passthrough morethan3
M O unknown force members
Fx o
o use moments about joints
Fy
apply at a joint
applied
Fray
In ran to 5N HINT
7
forces at fixedjointscan
compression
Itension
r go either way
i determine rn forces to appliedforces atjoints
g g
then do opposite same force to fixedjoint
Ay Try
mendo forces inbetween to determine tension
compression
Fy O Free Body Diagram
E Fa o
EMO 0
LOADINGS
if distributed loadings made upof D I splitinto simpler
shapes
way was
I
I
, SIMPLE TRUSSES
jointare noncollinear
force directions onthat
no faceapplied to thatjoint
all loadings applied atjoints
1
2 members
joined by smooth pins s
ve 3unknownforces applied to thejointof which 2 are
collinear
the3rdone notcollinear is me zeroforce
ve member should merebe no applied face on that
joint
ii
CASE A CASE B
method of joints method of sections
if entire nss is in
equilibrium
if entire miss is
section of moss is as well
in equilibrium
see choosing what to section
joint is as well o
ty o
x passthrough morethan3
M O unknown force members
Fx o
o use moments about joints
Fy
apply at a joint
applied
Fray
In ran to 5N HINT
7
forces at fixedjointscan
compression
Itension
r go either way
i determine rn forces to appliedforces atjoints
g g
then do opposite same force to fixedjoint
Ay Try
mendo forces inbetween to determine tension
compression
