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.
New Mexico ranked 36th in population in the US with an estimated total of 1,855,059 in 2002, an increase of 2% since 2000. Between 1990 and 2000, New Mexico's population grew from 1,515,069 to 1,819,046, an increase of 20.1%. The population is projected to reach 2,016,000 by 2005 and 2.6 million by 2025. The population density in 2000 was 15 persons per sq mi.