Aline that describes volume across the surface of an object or shape is called a line.

A line that describes volume across the surface of an object or shape is called a cross-contour line. These are lines that would reflect the eye's movements of what you see around. These describes form and volume as compared to contour lines which describe edges only. These lines would help in understanding a three dimensional form in a form of 2D. 

Iwould choose the same momentum because if they throw a baseball very light and not hard at all then doing it with a bowling ball won’t hurt that worse