Rotational inertia is described as which of the following?

Rotational inertia, also known as moment of inertia, is fundamentally defined as the reluctance of an object to change its state of rotation. This property depends on both the mass of the object and its distribution relative to the axis of rotation. When a force is applied to initiate a rotation, a higher moment of inertia means that it requires more torque to achieve the same angular acceleration compared to an object with a lower moment of inertia.

Understanding this concept is crucial in the context of physics and biomechanics, as it illustrates why large and heavy objects are harder to start or stop rotating compared to lighter ones. This principle is applied broadly, from understanding the dynamics of human movement in fitness training to analyzing the behavior of various physical systems in engineering and sports. In this case, the incorrect options do not accurately capture this definition; instead, they refer to aspects like speed or force, which do not define the intrinsic property of reluctance associated with rotational inertia.