Question

The potential energy of a pair of hydrogen atoms separated by a large distance 𝑥 is given by 𝑈(𝑥) = −𝐶6/𝑥 6 , where 𝐶6 is a positive constant. What is the force that one atom exerts on the other? Is this force attractive or repulsive?

Answer 1

$$F=-\frac{C_6}{x^7}$$

The force is negative that means the force is attractive in nature.