center of mass

noun

, Mechanics.

1. the point at which the entire mass of a body may be considered concentrated for some purposes; formally, the point such that the first moment of a physical or geometric object about every line through the point is zero. Compare moment ( def 8 ).

center of mass

1. A point in space determined by a distribution of mass (such as a solid object, a collection of objects, or a gas), such that a uniform force acting on the whole distribution acts as if the distribution were located at just that point. For example, the gravitational force on Earth attracts small objects as if it were pulling them from their center of mass (in this case, the center of mass is also called the center of gravity ). Two stars in orbit around each other revolve around their collective center of mass.
2. See also barycenter

Word History and Origins

Origin of center of mass¹

First recorded in 1875–80

Example Sentences

When a skateboarder hits the circular section of the half-pipe, they start crouched down, positioning their center of mass further from the center of rotation above their head.

From Los Angeles Times

The model represents a runner as a center of mass, with a hip that can rotate and a leg that can stretch.

From Science Daily

Eventually, when its nuclear batteries run out of juice for good, it will continue to quietly orbit the center of mass of the Milky Way for eternity.

From Salon

ALMATY, Kazakhstan — One evening in early January, Yerlan Zhagiparov left his home to see what was happening nearby at the city’s Republic Square, a center of mass political protests.

From New York Times

The objects might zoom by each other, or they might enter into an elliptical orbit around a shared center of mass.

From Scientific American