Momentum is conserved in case of motion under gravity because a object is pulled by the earth and the earth of pulled by the object. The momentum terms of the object and earth cancel each other out as the object has small mass but high velocity and the earth has very high mass and very small velocity in the opposite direction of the velocity of the object.
Southwick, Massachusetts. Southwick is a town in Hampden County, Massachusetts, United States. The population was 9,502 at the 2010 census. It is part of the Springfield, Massachusetts Metropolitan Statistical Area.
Sewickley Township, Westmoreland County, Pennsylvania. Not to be confused with New Sewickley Township, Beaver County, Pennsylvania or North Sewickley Township, Beaver County, Pennsylvania. Sewickley Avenue in Herminie. Sewickley Township is a township in Westmoreland County, Pennsylvania, United States. The population was 6,230 at the 2000 census.