# Homework Help: Bungee Jumping question

1. Apr 18, 2010

### aks_sky

I am a bit confused in this problem.

A person of mass 80 kg takes a bungee jump. At the lowest point of the jump the bungee cord is 90m in length and then at the lowest point of the next oscillation the cord has a length of 80m. when the person does eventually come to rest the length of the cord is 50m. the period of the small oscillations just before the person comes to rest is 6s. find the damping constant for the cord and its unstretched length.

What i tried:

Well i have been given the Period of the small oscillations which is 6s. Now to find the spring constant i use this:
$$T=2\cdot\pi\cdot\sqrt{\frac{m}{k}}$$
And then if use this next equation, The only thing i am not sure about is the Delta L. Since the length of the cord changes in the question.
$$mg=k\Delta L$$

Can someone help me clear up on the rope length and the unstretched part. I am just a but confused. and is there an easier way also to find the damping constant since i will have all the relevant parameters?

2. Apr 20, 2010

### aks_sky

anybody know?

3. Apr 22, 2010

### aks_sky

ok then. thank you!