Fundamentally, momentum conservation is linked to invariance under space translations. See Noether's theorem. If you want to find a system that does not conserve momentum you should look for situations where space is not uniform, e.g. balls rolling on the surface of a bowl, a planetary system (when the dynamics of the sun is neglected), etc.
Socorro is a city in Socorro County in the U.S. state of New Mexico. It is in the Rio Grande Valley at an elevation of 4,579 feet (1,396 m). In 2012 the population was 8,906.
Socorro is a city in El Paso County, Texas, United States. As of the 2000 census, the city population was 27,152. It is part of the El Paso Metropolitan Statistical Area. The city was reactivated in 1986 and has been a working city since then. It has a a council manager type of government with 5 city council members.