Extracted text: In a railroad classification yard, a 76-Mg freight car moving at 1.1 m /s at A encounters a retarder section of track at B which exerts a retarding force of 36 kN on the car in the direction opposite to motion. Over what distance x should the retarder be activated in order to limit the speed of the car to 3.2 m /s at C? 196 m 3.2 m B (Vertical scale exaggerated) C Part 1 Calculate the kinetic energies at A and C; Answers: TA = i kg m?/s? Tc = i kg m?/s?