A bungee jumper has a mass of 74.3 kg and falls a distance of 113 m before the bungee catches and sends the jumper upwards. 1. Assuming the jumper starts from rest, find their total mechanical energy.
2. Assuming energy is conserved, find the speed of the jumper just before the bungee catches.
3. After the bungee catches, the jumper returns to a maximum height of 98.3 m. How efficient is the bungee in returning the stored energy to the jumper?