Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

The stretch rule states that this quantity does not change when an object is distorted along its axis of rotation. The tensor for this quantity is symmetric, and is diagonal in some orientation, defining an object's principal axes. If this value is given for one axis of rotation it can be found for certain others using the (*) parallel axis theorem. It is calculated by summing or integrating mass times distance from an axis squared, and rotational kinetic energy is equal to this quantity times the square of the angular velocity. For 10 points, identify this quantity, the rotational analog of mass, which often has units of kilograms times meters squared, symbolized I.
Science