Your adventurous friend Lola goes bungee jumping

Your adventurous friend Lola goes bungee jumping. She leaps from a bridge that is 100 m above a river. Her bungee cord has an un-stretched length of 50 m and a spring constant k = 600 N/m. Lola has a mass of 48 kg. a) How fast is she falling when she just starts to stretch the cord? How long does it take for Lola to reach this point? b) Lola stretches the bungee cord and it brings her to a stop. She then bounces back up again. What type(s) mechanical energy does the system (Lola and the bungee cord) have just before she jumps? (i.e., gravitational PE, elastic PE, kinetic energy, etc.) What type(s) of energy does the system have at the instant she comes to rest at her lowest point? c) What is her height above the river at her lowest point?