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.
The population in 2018 is estimated at 6.90 million, up from the 6,547,629 figure recorded during the last official nationwide Census held in 2010. Massachusetts also has a fairly healthy population growth rate of 0.75% annually, which ranks 28th in the United States.