Momentum is not conserved if there is friction, gravity, or net force (net force just means the total amount of force). What it means is that if you act on an object, its momentum will change. This should be obvious, since you are adding to or taking away from the object's velocity and therefore changing its momentum.
Somerville, Massachusetts. Somerville (/ËsÊmÉrvÉªl/ SUM-Ér-vil) is a city located directly to the northwest of Boston, in Middlesex County, Massachusetts, United States. As of 2010, the United States Census has the city with a total population of 75,754 people, and is the most densely populated municipality in New England.
Boston is the state capital and largest city in Massachusetts. The population of the city proper is 645,966, and Greater Boston, with a population of 4,628,910, is the 10th largest metropolitan area in the nation. Other cities with a population over 100,000 include Worcester, Springfield, Lowell, and Cambridge.