A violin creates tension in its ①strings and gives each of them an equilibrium shape: a straight line. A tight violin string can be viewed as composed of many individual pieces that are connected in a chain as in the above two figures. When the string is ②straight, as in Figure 1, its tension is uniform, and the two outward forces on a given piece sum to zero; they have equal magnitudes and point in ③opposite directions. With no net forces acting on its pieces, the string is in equilibrium. But when the string is ④curved, as in Figure 2, the outward forces on its pieces no longer sum to zero. Although the string’s uniform tension still gives those outward forces equal magnitudes, they now point inslightly different directions, and each piece experiences a ⑤zero net force. The net forces on its pieces are restoring forces, which will cause the string to vibrate and thus make sounds.