Particle A and particle B, each of mass M, move along the x-axis exerting a force on each other. The potential energy of the system of two particles associated with the force is given by the equation U = β / r 2 , where r is the distance between the two particles and β is a positive constant. At time t = 0, particle A is located at x = 2D with an initial speed of v0 to the left, and particle B is at rest at the origin, as shown in the figure above. Which of the following equations could be used to find rMIN, the minimum distance between the masses as particle A approaches particle B? Responses