Energy Question -- Chain sliding off frictionless table 1. The problem statement, all variables and given/known data Here is the problem that's confusing me: A frictionless chain of length 2.00m is held with 20.0% of its length hanging over the edge of a table. The chain is then released. Determine its speed the moment the entire chain comes off the table. (Answer = 4.34m/s) 2. Relevant equations I assumed this was an energy related question and that the equations for Kinetic/Potential energy would apply. 3. The attempt at a solution I wasn't really sure how to approach this problem but I tried PE = KE since at first the chain is just hanging and then at the end the entire thing is off the table. so I tried PE = KE mgh = 1/2mv^2 (.8*mass)(g)(1.6m) = 1/2(1*mass)(v^2) I thought you might only need to use 80% of the total mass of the string for the PE since 20% is hanging off. And I thought h would only be 1.6 since that's the remaining length of the string that still needed to fall. But I didn't get the correct answer and I'm probably totally wrong with my thinking but this question confused me :s Any help would be appreciated.