Atrain car has a mass of 10,000 kg and is moving at +3.0 m/s. it strikes an identical train car that is at rest. the train cars combine.

what is the magnitude of the final velocity of the combined cars?

0 m/s

1.5 m/s

3.0 m/s

6.0 m/s

Which statement is the best definition of an atom? a) anything that has mass and occupies space. b) the smallest particle that has the properties of an element. c) a substance that cannot be broken down chemically into simpler substances. eliminate d) the smallest unit of a substance that exhibits all of the properties characteristic of that substance.