Help! I Don't Know How To Do This

[leggythegoose]

Homework Statement

A small block with mass 0.0400 kg is moving in the xy-plane. The net force on the block is described by the potential-energy function U(x,y)=(5.80 J/m^2)x^2 − (3.90 J/m^3)y^3. What is the magnitude of the acceleration of the block when it is at the point x=0.39 m, y=0.61 m? What is the direction of the acceleration of the block when it is at the point x=0.39 m, y= 0.61 m?

Relevant Equations

Force and potential energy in 3D?

I have no idea how to do this honestly.

 

[TSny]

I have no idea how to do this honestly.

In order to receive help you must show some attempt at solving the problem. If you can't get started, can you identify anything that you have covered in class or in your book that you believe would be relevant to this problem? Would the problem be easier if they had asked for the force on the particle rather than the acceleration?