Biomedical Engineering Reference
In-Depth Information
a
b
C.G.
underneath
the seat
axis
C.G.
axis
c
d
e
C.G.
C.G.
axis
axis
axis
Fig. 3.1
Illustration of bodies under, or not, the action of torque of gravitational force. In each
situation, the center of gravity C.G., the weight, the support point seen as an axis about which the
body can rotate, and its respective normal force are represented. (
a
) Acrobat, (
b
) inclined chair,
(
c
) yoga's headstand posture (sirsasana), (
d
) a person rising from a chair, (
e
) a person bending over
to touch his toes with heels and back against a wall
will happen next: they will remain at the same position or will rotate or fall.
The center of gravity of each body is represented in Fig.
3.1
as well as the point
of support.
The conclusion for each situation is obtained by considering that the weight
force of each body acts at its center of gravity and can exert a torque about the point
of support, considered as an axis of rotation. As the weight force is always vertical
