The gas space above the water in a closed storage tank contains nitrogen at $80 \mathrm{F}, 15 \mathrm{lbf} / \mathrm{in}^{2}$ Total tank volume is $150 \mathrm{ft}^{3}$, and there is 1000 Ibm of water at $80 \mathrm{F}$. An additional $1000 \mathrm{lbm}$ of water is now forced into the tank. Assuming constant temperature throughout, find the final pressure of the nitrogen and the work done on the nitrogen in this process