About: http://webisa.webdatacommons.org/168456679

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Since force is a vector quantity, the vector summation of all parts of the shell contribute to the net force, and this net force is the equivalent of one force measurement taken from the sphere is midpoint, or center of mass (COM).
http://www.w3.org/ns/prov#wasQuotedFrom	boundless.com