# Angular Momentum Essay

1430 Words6 Pages
Angular momentum and its properties were devised over time by many of the great minds in physics. Newton and Kepler were probably the two biggest factors in the evolution of angular momentum. Angular momentum is the force which a moving body, following a curved path, has because of its mass and motion. Angular momentum is possessed by rotating objects. Understanding torque is the first step to understanding angular momentum.Torque is the angular "version" of force. The units for torque are in Newton-meters. Torque is observed when a force is exerted on a rigid object pivoted about an axis and. This results in the object rotating around that axis. "The torque ? due to a force F about an origin is an inertial frame defined to be ? ?…show more content…
It is common to define a mass density in various forms. For a three-dimensional object, it is appropriate to use the volume density, that is, mass per unit of volume: ? = lim ?m = dm ?v?0 ?d dVdm = ? dV therefore: I = ? ?r2 dV."5Since every different shape has all of its mass in different places relative to the axis of rotation a different final, simplified formula results for every shape. The shapes that will be focused on (in presentation) are the: hoop of a cylindrical shell, solid cylinder or disk, and the rectangular plane, with formulas: ICM = MR2, ICM = 1/2 MR2 , and ICM = 1/12 M(a2 + b2) respectively (see diagrams on sheet titled "Moments of Inertia of Some Rigid Objects").Similar to the Law of Conservation of Linear Momentum is the Law of Conservation of Angular Momentum. This law applies to rotating systems that have no external torques or moments applied to them. This law helps to explain why a rotating object will start to spin faster (with a greater angular velocity) if all or some of its mass is brought inward towards its rotating axis or why it would start to rotate with a decreased angular velocity if some of its mass is "spread" out away from its rotating axis. An example of this is the slowly spinning figure skater who pulls his arms close to himself and suddenly speeds up his angular velocity. When he wants to decrease his angular velocity (or his velocity of rims) he merely spreads out his arms again and