PURPOSE: To determine the minimum value of the spring constant of a bungee rope to ensure a safe jump.

DESCRIPTION: Student of mass M jumps from a cliff of height H tied to a bungee rope of unstretched length Lo. Assume a vertical jump with initial velocity of zero. Neglect air resistance and mass of the rope.

When the spider jumps off the platform the spring extends to within a few inches (or centimeters in physics) of the floor before pulling the spider back up.

SUGGESTIONS: DANGER - IMPORTANT NOTE: Bungee cords are made of shock cords (elastomers) or from rubber. They DO NOT behave as linear springs. It would be dangerous to assume linearity of a real bungee jumping cord and make calculations on this basis.

REFERENCES: (PIRA unknown.) See Demonstration Reference File for sample calculation.

EQUIPMENT: Spring on support with jump platform, spider.

SETUP TIME: 5 min.