<s>
In	O
physics	O
and	O
engineering	O
,	O
a	O
free	B-Application
body	I-Application
diagram	I-Application
(	O
FBD	O
;	O
also	O
called	O
a	O
force	B-Application
diagram	I-Application
)	O
is	O
a	O
graphical	O
illustration	O
used	O
to	O
visualize	O
the	O
applied	O
forces	O
,	O
moments	O
,	O
and	O
resulting	O
reactions	O
on	O
a	O
body	O
in	O
a	O
given	O
condition	O
.	O
</s>
<s>
The	O
body	O
may	O
consist	O
of	O
multiple	O
internal	O
members	O
(	O
such	O
as	O
a	O
truss	B-Device
)	O
,	O
or	O
be	O
a	O
compact	O
body	O
(	O
such	O
as	O
a	O
beam	O
)	O
.	O
</s>
<s>
Free	B-Application
body	I-Application
diagrams	I-Application
are	O
used	O
to	O
visualize	O
forces	O
and	O
moments	O
applied	O
to	O
a	O
body	O
and	O
to	O
calculate	O
reactions	O
in	O
mechanics	O
problems	O
.	O
</s>
<s>
In	O
the	O
educational	O
environment	O
,	O
a	O
free	B-Application
body	I-Application
diagram	I-Application
is	O
an	O
important	O
step	O
in	O
understanding	O
certain	O
topics	O
,	O
such	O
as	O
statics	O
,	O
dynamics	O
and	O
other	O
forms	O
of	O
classical	O
mechanics	O
.	O
</s>
<s>
A	O
free	B-Application
body	I-Application
diagram	I-Application
is	O
not	O
a	O
scaled	O
drawing	O
,	O
it	O
is	O
a	O
diagram	O
.	O
</s>
<s>
The	O
symbols	O
used	O
in	O
a	O
free	B-Application
body	I-Application
diagram	I-Application
depends	O
upon	O
how	O
a	O
body	O
is	O
modeled	O
.	O
</s>
<s>
Free	B-Application
body	I-Application
diagrams	I-Application
consist	O
of	O
:	O
</s>
<s>
Free	B-Application
body	I-Application
diagrams	I-Application
may	O
not	O
represent	O
an	O
entire	O
physical	O
body	O
.	O
</s>
<s>
Thus	O
if	O
rotation	O
of	O
the	O
body	O
and	O
torque	B-General_Concept
is	O
in	O
consideration	O
,	O
an	O
indication	O
of	O
size	O
and	O
shape	O
of	O
the	O
body	O
is	O
needed	O
.	O
</s>
<s>
A	O
free	B-Application
body	I-Application
diagram	I-Application
should	O
not	O
show	O
:	O
</s>
<s>
(	O
For	O
example	O
,	O
if	O
an	O
entire	O
truss	B-Device
is	O
being	O
analyzed	O
,	O
the	O
forces	O
between	O
the	O
individual	O
truss	B-Device
members	O
are	O
not	O
included	O
.	O
)	O
</s>
<s>
In	O
an	O
analysis	O
,	O
a	O
free	B-Application
body	I-Application
diagram	I-Application
is	O
used	O
by	O
summing	O
all	O
forces	O
and	O
moments	O
(	O
often	O
accomplished	O
along	O
or	O
about	O
each	O
of	O
the	O
axes	O
)	O
.	O
</s>
<s>
A	O
simple	O
free-body	B-Application
diagram	I-Application
,	O
shown	O
above	O
,	O
of	O
a	O
block	O
on	O
a	O
ramp	O
,	O
illustrates	O
this	O
.	O
</s>
<s>
They	O
are	O
related	O
to	O
and	O
often	O
used	O
with	O
free	B-Application
body	I-Application
diagrams	I-Application
,	O
but	O
depict	O
only	O
the	O
net	O
force	O
and	O
moment	O
rather	O
than	O
all	O
of	O
the	O
forces	O
being	O
considered	O
.	O
</s>
