TWO field markings for the Black Vulture

The black vulture (Coragyps atratus), also known as the American black vulture, is a bird in the New World vulture family whose range extends from the northeastern United States to Peru, Central Chile and Uruguay in South America. Although a common and widespread species, it has a somewhat more restricted distribution than its compatriot, the turkey vulture, which breeds well into Canada and south to Tierra del Fuego. It is the only extant member of the genus Coragyps, which is in the family Cathartidae. Despite the similar name and appearance, this species is unrelated to the Eurasian black vulture, an Old World vulture in the family Accipitridae (which includes eagles, hawks, kites, and harriers). It inhabits relatively open areas which provide scattered forests or shrublands. With a wingspan of 1.5 m (4.9 ft), the black vulture is a large bird though relatively small for a vulture. It has black plumage, a featherless, grayish-black head and neck, and a short, hooked beak.

the displacement produced by the body.  

the amount of force subjected to the body.  

the angle between the direction of force and displacement