It is not enough fro all the
forces in each direction to equal each other to keep a body in
equilibrium.
The bar on the left below is
balanced. The upwards forces equal the downwards forces. The bar on
the right is not balanced. The bar on the right will turn in the
direction of the arrows.
There is another condition
that must be satisfied for equilibrium.
The Principle of Moments
For a body to remain in
equilibrium, the sum of the clockwise moments (Force*Distance) must
be equal to the sum of the anticlockwise moments about each pivot
point. In the diagram above, the pivot points are shown as circles on
the plank.
The Principle of Moments can be used to find unknown
forces of unknown distances.
No comments:
Post a Comment