The turning effect of a force about a point is the _______ moment of a force.

The turning effect of a force about a point is referred to as the moment of a force, specifically characterized by how it generates rotation around that point. The term "moment" is a measure of the tendency of a force to cause an object to rotate about an axis or pivot point.

The concept is rooted in the physics of torque, which is mathematically expressed as the product of the force and the perpendicular distance from the pivot point to the line of action of the force. Therefore, the idea of "first" moment can be associated with the fundamental understanding of how forces interact with leverage and rotation.

Understanding moments is crucial in the field of power engineering, as it applies to various components such as gears, levers, and machinery where rotational motion is essential. Through this perspective, it's clear why the term "first" would align closely with the basic definition of a moment, establishing a foundation for further understanding in both mechanical and engineering principles.

The other options do not accurately reflect the established terminology or dimensional analysis associated with moments in physics. Each lacks the fundamental connection to rotational dynamics that the term "first moment" represents.