Biomedical Engineering Reference
In-Depth Information
Fig. 5.1
Representation
of the first class lever,
denoting the position of
the axis of rotation,
perpendicular to this page,
the force of action and of
resistance, and their arms.
An example of a first class
lever used to lift a heavy
object is also represented
d
R
d
A
axis
F
A
F
R
Fig. 5.2
Representation
of the second class lever,
indicating the position of
the axis of rotation in
relation to the force of
action and of resistance,
and the arms of these forces.
The sketch of a second class
lever utilized to transport
heavy loads is also
exemplified
d
A
F
A
d
R
axis
F
R
5.4.1 First Class Levers
All of the systems in which the fulcrum or pivot (axis of rotation) is between
the points of application of the action force and that of the resistance belong to this
category. Figure
5.1
shows a generic representation of a first class lever. The force
of reaction at the fulcrum is not drawn in this figure as in Figs.
5.2
and
5.3
. The mass
