## College Physics (4th Edition)

We can find the required gauge pressure: $P_{abs} = P_{atm}+P_g$ $P_g = P_{abs} - P_{atm}$ $P_g = 4.0~atm - 1.0~atm$ $P_g = 3.0~atm$ We can convert the gauge pressure to units of $N/m^2$: $3.0~atm \times \frac{1.01\times 10^5~N/m^2}{1~atm} = 3.03\times 10^5~N/m^2$ We need to find the depth $h$ below the surface with this gauge pressure: $\rho~gh = 3.03\times 10^5~N/m^2$ $h = \frac{3.03\times 10^5~N/m^2}{\rho~g}$ $h = \frac{3.03\times 10^5~N/m^2}{(1.0\times 10^3~kg/m^3)(9.80~m/s^2)}$ $h = 31~m$ At a depth of 31 meters, the water pressure is 4.0 atm.