A ball is fixed in the middle of a string of length 2l. What is the total force acting on the ball from the side of the string if its transverse displacement from the equilibrium position is x ≪ l, and the string tension force F does not depend on the displacement? Why, for small displacements, can we consider the dependence of the force acting on the ball on x to be linear? What is the direction of this force with respect to the displacement? Find how the potential energy of the ball depends on the small displacement x. What is the velocity of the ball when it passes its equilibrium position if its maximum displacement is x₀? The mass of the ball is m.