use conservation of angular momentum …Moment of inertia, also known as rotational inertia, is a measure of an object's resistance to changes in its rotational motion. It depends on an object's mass, shape, and distribution of mass.
Moment of inertia is a property of an object that describes its distribution of mass, while mass is a measure of the amount of matter in an object. They are related, but not the same concept.
Angular velocity is the rate at which an object rotates around an axis. It is measured in radians per second (rad/s) or degrees per second (deg/s).
Moment of inertia and angular velocity are related by the equation I = m*r^2, where I is the moment of inertia, m is the mass of the object, and r is the distance from the axis of rotation. This means that an object with a larger moment of inertia will require more torque to achieve the same angular velocity as an object with a smaller moment of inertia.
There are specific formulas for calculating moment of inertia for common shapes, such as cylinders, spheres, and rectangular prisms. For more complex shapes, the parallel axis theorem can be used to calculate the moment of inertia about a specific axis by adding the moment of inertia about a parallel axis and the product of the mass and the square of the distance between the axes.