Consider a system to be one train car moving toward another train car at rest. When the train cars collide, the two cars stick together. What is the total momentum of the system after the collision?
800 kg • m/s
1,600 kg • m/s
2,400 kg • m/s
4,000 kg • m/s

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length (in m) of a column of water 1.45 km high for a temperature increase of 1.12°c. assume the column is not free to expand sideways. as a model of the ocean, that is a reasonable approximation, as only parts of the ocean very close to