Question 7
Two forces inclined to each other are applied to a ring by spring balances B and C. Given the resultant of those two forces, what must be done to bring the ring to rest?
The right answer is the one marked above.
Apply a force equal and opposite to the resultant. The resultant of all three is then zero.
Its line of action must also pass, coplanar, through the point where the lines of the other two forces meet — that is the third condition.