Suppose we have a gradient flow in $\mathbb{R}^n$ :
$$\frac{d}{dt}x(t)=-\nabla F(x(t)), \qquad x(0)=x_0.$$
where $F : \mathbb{R}^n \to \mathbb{R}$ and $x : \mathbb{R}_+ \to \mathbb{R}^n$. What are some classical examples (or toy models) from physics, chemistry or biology for the above Euclidean gradient flow? References are also welcome!
