The lowest center of gravity of all possible states of a rectangular block is considered as……………a.Metastableb.Neutralc.Unstabled.Stable

To determine the correct answer regarding the center of gravity of a rectangular block, let's analyze each option:

1. Metastable: This state is often associated with a system that can remain in a local minimum of energy but may transition to a more stable state with a small perturbation.

2. Neutral: A neutral equilibrium means that any small displacement of the object does not result in a restoring force to return it to its original position.

3. Unstable: An unstable equilibrium indicates that a slight disturbance will lead the system to move away from its equilibrium position.

4. Stable: In stable equilibrium, if the object is displaced slightly, it will return to its original position due to the restoring forces acting on it.

Conclusion

In the case of a rectangular block, the lowest center of gravity corresponds to a stable equilibrium. Thus, the correct answer is:

d. Stable

The rationale behind this choice is based on the fact that the center of gravity determines the stability of the block's position; a lower center of gravity generally implies a more stable configuration against tipping or rolling.