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How to Calculate the Angular Momentum Through an Axis

An angular momentum is a characteristic of an angular motion such as rotation. This value is the mathematical product of the angular velocity and the momentum of inertia. The momentum of inertia plays the same role in the angular motion as the mass does in the linear motion. The momentum of inertia depends upon the shape of the rotating object such as a cylinder, a rod or a sphere as well the location of the rotation axis.

Instructions

- 1
  Find out the formula to calculate the moment of inertia. For example, if the rotation axis goes through the center of a cylinder then moment of inertia is (M x R^2)/2 where "M" and "R" denote the mass and radius of the cylinder.
- 2
  Raise the radius of the cylinder to square. For example, if the radius is 0.4 meters then 0.4 x 0.4 = 0.16 square meters.
- 3
  Multiply the square radius by the mass and then by 0.5 to calculate the moment of inertia. In this example, if mass is 5 kilograms then the moment of inertia is 0.16 x 5 x 0.5 = 0.4.
- 4
  Multiply the moment of inertia by the angular velocity to calculate the angular momentum. For example, if the angular velocity is 25 degrees per second then the angular momentum is 0.4 x 25 = 10.

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