A light spring with a spring constant of 80.0 N/m rests vertically on a table, as shown in Figure 9-23(a). A 2.00 g balloon is filled with helium (0°C and 1 atm pressure) to a volume of 5.00 m3 and connected to the spring, causing the spring to stretch and expand, as in Figure 9-23(b). How much does the spring stretch when the balloon-and-spring system is in equilibrium? (The density of helium is 0.179 kg/m3)