What Is the Distance at Which There Is No Net Force Between Two Atoms?

[baubletop]

Homework Statement

The potential energy of two atoms separated by a distance r may be written as:

U(r) = 4U_atomic * [(r₀/r)¹² - (r₀/r)⁶]

>Given r₀ = 4.0 A_o and U_atomic = -0.012795 eV, what is the distance at which there is no net force between the atoms? Express your answer in terms of A_o.

>What is the potential energy at the position where the net force is 0 N? Express your answer in terms of eV.

Homework Equations

The above equation.

The Attempt at a Solution

I tried using Coulomb's Law, but I don't know the charges so it's not very helpful. Finding the total energy is also not relevant since I don't know mass or velocity. I'm pretty stuck here. I know once I find the first part I can find the second part easily, but I feel like I'm overlooking something simple for the first part of the question.

 

[Doc Al]

Hint: What's the relationship between force and the potential function? (Use calculus.)

 

[baubletop]

F = -dU/dr :) I tried it and it worked! Thanks for the hint!