A particle of mass m is constrained to move on the x-axis. A force F acts on the particle. F always points toward the position labelled E. For example, when the particle is to the left of E, F points to the right. The magnitude of F is constant except at point E where it is zero. The system is horizontal. F is the net force acting on the particle. The particle is displaced a distance A towards left from the equilibrium position E and released from rest at t = 0. What is the velocity-time graph of the particle is