What does it mean to say that momentum is conserved? when momentum or any other object in physics doesn't change..... momentum = momentum before and after the collision. Elastic collision
The 2016 Springfield, Illinois, population is 116,565. There are 1,955 people per square mile (population density). The median age is 38.7. The US median is 37.4. 44.11% of people in Springfield, Illinois, are married. 14.83% are divorced.
The United States Census Bureau estimates that the population of Illinois was 12,802,023 in 2017, moving from the fifth-largest state to the sixth-largest state (losing out to Pennsylvania). Illinois' population declined by 33,700 people from July 2016 to July 2017, making it the worst decline of any state in the U.S. in raw terms.