A positive condition of stability corresponds to which relation between M and G?

• A. M over G
• B. G=M
• C. G over M
• D. M-G

Answer: (A)

When assessing stability, the key is whether the moment that appears when the system is tilted acts to return it to upright. This restoring tendency shows up when the overturning moment M and the weight G share the same sense, meaning they have the same sign. Expressing that relationship as a ratio, M/G, and requiring it to be positive makes clear that the restoring effect is active per unit weight. A positive M/G indicates a stable, restoring response as the body is displaced.

The other forms don’t capture that directional restoring effect. Stating G equals M imposes a specific equality rather than the needed sign relationship. Taking the reciprocal G/M changes the meaning of the ratio and can invert the interpretation, and subtracting M and G yields a difference rather than a measure of the restoring tendency.