Working mass Working mass Working mass, also referred to as reaction mass, is a mass against which a system operates in order to produce acceleration. In the case of a rocket, for example, the reaction mass is the fuel shot backwards to provide propulsion. All acceleration requires an exchange of momentum, which can be thought of as the "unit of movement". Momentum is related to mass and velocity, as given by the formula "P = mv," where "P" is the momentum, "m" the mass, and "v" the velocity. The velocity of a body is easily changeable, but in most cases the mass
Constant linear velocity CAV systems are used. This is because seek performance would be greatly affected during random access by the requirement to continually modulate the disc's rotation speed to be appropriate for the read head's position. Zoned Constant Linear Velocity (ZCLV) is a modification of CLV for high speed CD and DVD recorders. Early model recorders were CLV drives. The recording speed on such drives was rated in multiples of 150 KiB/s; a 4X drive, for instance, would write steadily at around 600 KiB/s. The transfer rate was kept constant by having the spindle motor in the drive vary in speed and