Video Transcript
Complete the following: If three
coplanar and equilibrium forces are represented by the sides of a triangle taken in
one cyclic order, then the lengths of the sides of the triangle are proportional to
what.
The correct answer here is the
magnitude of the forces. If we consider three forces π
sub
one, π
sub two, π
sub three that act at a point and theyβre in equilibrium, then
they can be redrawn as a triangle, providing we consider the order and direction of
the forces. We begin by drawing the force π
sub one as shown. Then we move on to π
sub two. This begins at the terminal or
endpoint of the force π
sub one. Finally, we repeat this process
with the third force π
sub three. This begins at the terminal point
of π
sub two and travels in the same direction as in our first diagram. Its terminal point will correspond
to the initial point of π
sub one. And we have therefore created a
triangle of forces.
The magnitude of these forces is
proportional to the lengths of the sides of the triangle drawn. This is true of any three coplanar
forces in equilibrium.