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kcolman
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Homework Statement
Exercise 1. Two bungee jumpers jump from a bridge. Jumper A is fastened to a bungee cord and holding on to jumper B. The cord has a stiffness k = 80 lb/ft. Find the unstretched length of the cord if the two students just reach the surface of the water at the maximum displacement. If student A let's go of student B at the surface of the water. Is there a problem for student A on the return? The distance between the bridge and water is 120 ft.
Homework Equations
T1 + ƩU1-2 = T2
U1-2 = -WΔy Work of a weight
U1-2 = -ksΔs2 Work of a Spring Force
The Attempt at a Solution
I solved the first part by using the principle of work and energy, setting T1 and T2 to zero and solving for the s-initial. However, I'm having trouble with the second part. I know that the potential energy from the first part gets transferred to the bungee jumpers kinetic energy in his ascension, and that his final height will be higher than if he didn't let go of the other bungee jumper. Also, I know his final kinetic energy will be zero at his maximum height, and I think the question wants to know if this height will be greater than the height of the bridge over water. Any thoughts?