Using Conservation of Energy to Analyze a Potential Energy Graph

[chuuke]

Homework Statement

I'm trying to figure out how to do D) and relate time to this potential energy graph.

Homework Equations

All I really know is that F = -dU/dx

The Attempt at a Solution

I tried to do something with F = ma
and a = d²x/ dt²
and then set the - derivative of U(x) equal to the above equation
but I can't really get an answer, and am quite frustrated cause I don't know how to go about answering this.

 

[RedDelicious]

You need to use the conservation of energy. When released from B, what is going to be the velocity at any point? How is that related to position?

Also, what position do you have as the turning point? Based on that, what kind of motion do you expect?