Kinetic Energy 3. A father and son went jogging. If the son weighs 50 kg and the father weighs 75 kg, and both ran at a speed of 5 ms, who had the greater kinetic energy? What is the kind energy of a 47.30-kg man running at a speed of 5.0 m/s? A roller coaster car with a mass of 535 kg is travelling at a speed of 128 m's. What is the kinetic energy of the roller coaster car?​