A spring is attached at one end to a fixed point and hangs vertically with a cube attached to the other end. The cube is initially held so that the spring has zero extension, as shown in Fig. 3.1. [Figure 3.1] The cube has weight 4.0N and sides of length 5.1cm. The cube is released and sinks into water as the spring extends. The cube reaches equilibrium with its base at a depth of 7.0cm below the water surface, as shown in Fig. 3.2. [Figure 3.2] The density of the water is 1000kgm⁻³.