Moment of inertia is diagonal and torques around the axes act independently of each other. When a body is free to rotate around an axis, torque must be applied to change its angular momentum. The amount of torque needed to cause any given angular acceleration (the rate of change in angular velocity) is proportional to the moment of inertia of the body. Moment of inertia may be expressed in units of kilogram meter squared (kg·m) in SI units and pound-foot-second squared (lbf·ft·s) in imperial or US units. Moment of inertia plays the role in rotational kinetics that mass (inertia) plays in linear kinetics
Constant linear velocity of CLV that is used on the Laserdisc format. The initial specification of CLV (as it applies to laserdisc) results in several playback artifacts to be present in the audio/video portion as well as compatibility problems with Laserdisc players as produced by different manufacturers. In the mid 1980s, Pioneer Electronics introduced the CAA scheme where the speed in rotation of the Laserdisc was lowered in steps and eliminated most playback artifacts and compatibility problems. Since its introduction, most manufacturers of Laserdiscs adopted the CAA format but still referred to their CAA-encoded product as CLV. Constant linear velocity In optical storage,