Sara is testing how well bungee jumping cords work. She has cords wrapped in rubber, nylon, and canvas. She wants to know how much energy a person loses each time they bounce using the cord. She designs an experiment where she attaches a mass to each bungee cord and drops it. Then, she measures how high the mass bounces back up to find its final energy. Which of the following would tell Sara how much energy each bungee loses?