A piston/cylinder setup (Fig. P4.68) contains 1 kg of water at $20^{\circ} \mathrm{C}$ with a volume of $0.1 \mathrm{m}^{3} .$ Initially, the piston rests on some stops with the top surface open to the atmosphere, $P_{0},$ and a mass such that a water pressure of $400 \mathrm{kPa}$ will lift it. To what temperature should the water be heated to lift the piston? If it is heated to saturated yapor, find the final temperature, volume, and work,