Biomedical Engineering Reference
In-Depth Information
Fig. 3.10
Body in stable
equilibrium, since it will
return to its original position
when disturbed slightly, as
indicated
Fig. 3.11
Body in unstable
equilibrium, as it will
assume a new position when
released after undergoing a
small displacement as
indicated
Fig. 3.12
Body in neutral
equilibrium, as it will
remain in a similar position
when released, after a small
displacement
Example 3.5
Consider an adult with 70 kg mass and 1.70 m height, seated on the
floor, with crossed arms and outstretched legs, as shown in the figure of Example
3.5. It is not very easy to remain in this posture during a long time. The figure shows
the lateral cut, and the table of Example 3.5 gives the
x
and
y
coordinates of the
center of gravity of some segments, as well as the respective masses. The C.G. of
head and of neck-trunk-crossed arms is vertically aligned at a distance of 81 cm
from the sole of the feet.
y
81 cm
x
