| 73 / | HD | MEASURING AND TESTING | 
| 488 | DF | SPEED, VELOCITY, OR ACCELERATION {29} | 
| 514.01 | DF | .~ Acceleration determination utilizing inertial element {8} | 
| 514.02 | DF | .~.~ Angular acceleration {2} | 
| 514.03 | ![]()  | .~.~.~ Fluid or fluent inertial mass (e.g., electrons, ions, plasma) |