Question 12
When is a pivoted rod in equilibrium under moments?
The right answer is the one marked above.
The clockwise moment must equal the anticlockwise moment. That is, F1 × d1 = F2 × d2. The resultant moment is then zero, so the rod does not turn.
It is the products that must be equal, not the forces. A small force applied far enough out can hold a large one.