Final answer:
The angularity control beneath a dimension applies to the angle of the specified feature, maintaining it within the defined tolerance, which is essential for precise engineering and component fit.
Step-by-step explanation:
When an angularity control is shown beneath a feature of size dimension in technical drawings or engineering specifications, it refers to the tolerance within which the angle of the specified feature must be maintained. The angularity control applies to the ideal or theoretical exact conical, cylindrical, planar, or other angular feature outlined by the dimension. The feature must be within the angular tolerance defined, regardless of the feature's actual size within its size tolerance. It's crucial for ensuring that parts fit together correctly and function as intended, especially in high-precision engineering applications.
An example is the rotation of a nebula. If we assume that the angular momentum is conserved and apply it to a nebula's rotation, as its size changes, the rotation period must also change to maintain a constant angular momentum (considering the relationship D²/P, where D is the diameter and P is the period of rotation). For instance, if a solar nebula with a diameter of 10,000 AU and a rotation period of 1 million years shrinks to a diameter of 40 AU, its rotation period would decrease significantly to conserve angular momentum.