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. a train 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?

Determine the time it takes for a satellite to orbit the earth in a circular "near-earth" orbit. the definition of "near-earth" orbit is one which is at a height above the surface of the earth which is small compared to the radius of the earth, so that you may take the acceleration due to gravity as essentially the same as that on the surface. does your result depend on the mass of the satellite?