A freight car with a mass of 2500kg rolls down an inclined track through a vertical distance of 2.0m. At the bottom of the incline, on level track, the car collides and couples with an identical second freight car that was at rest. (A) What was the Kinetic energy of the first freight car before collision? (B) What was its velocity before collision? (C) What percentage of the initial kinetic energy is lost in the collision?