Calculating the Final Height of Chris's Bungee Jump

[gillyr2]

Homework Statement

Chris jumps off a bridge with a bungee cord tied around his ankle. He falls for 15m before the bungee cord begins to stretch. Chris's mass is 75kg and we assume the cord obeys Hooke's law F = -kx, with k=50N/m. If we neglect air resistance estimate how far below the bridge Chris's foor will be before coming to a stop. Ignore the mass of the cord and treat Chris as a particle.

Homework Equations

well i know h = 60m. but i don't know how I am suppose to get there.

The Attempt at a Solution

no idea what so ever

 

[gillyr2]

pleae someone help

 

[Doc Al]

Use conservation of energy.

 

[gillyr2]

how exactly do i encorporate hookes law in the conservation of energy equation?

 

[Doc Al]

What's the expression for the elastic potential energy stored in a stretched spring?

 

[tiny-tim]

"Relevant equations"

Hi gilly!

how exactly do i encorporate hookes law in the conservation of energy equation?

Whoa! Don't do it all at once. Don't start incorporating one thing into another.

You have two objects - Chris and the cord.

What is the energy of each?

Write them down separately. Then go from there.