1. The problem statement, all variables and given/known data A helium-filled balloon at atmospheric pressure is tied to a 3.1 m long, 0.100 kg string. The balloon is spherical with a radius of 0.40 m. When released, it lifts a length (h) of the string and then remains in equilibrium as in Figure P9.78. Determine the value of h. When deflated, the balloon has a mass of 0.25 kg. (Hint: Only that part of the string above the floor contributes to the load being held up by the balloon.) 2. Relevant equations P2 = P1 + dg(y1 - y2) d = density 3. The attempt at a solution First I determine the pressure of the balloon by using P = mg/A, and I got 4.874 Pa Then I use the equation P2 = P1 + dg(h) 4.874 = (0) + (1.29)(9.8)(h). The 1.29 is density of air. I have no idea why I set p1 equal 0. The answer I got is wrong and Im stuck. Help please.