## College Physics (4th Edition)

The Dutch boy must exert a force of $13.1~N$
We can find the pressure at a depth of 3.0 m under the water surface: $P_{abs} = P_{atm}+P_g$ $P_{abs} = P_{atm}+\rho~gh$ $P_{abs} = (1.01\times 10^5~N/m^2)+(1025~kg/m^3)(9.80~m/s^2)(3.0~m)$ $P_{abs} = 1.31\times 10^5~N/m^2$ We can find the force the Dutch boy must exert: $F = P~A$ $F = (1.31\times 10^5~N/m^2)~(1.0\times 10^{-4}~m^2)$ $F = 13.1~N$ The Dutch boy must exert a force of $13.1~N$.