Question

A swimming pool of depth 2.7 m is filled with ordinary (pure) water (ρ = 1000 kg/m3). (a) What is the pressure at the bottom of the pool? Pa

(b) When the pool is filled with salt water, the pressure changes by 4.5 103 Pa. What is the difference between the density of the salt water and the density of pure water? kg/m3

Answer 1

First, find pressure 1.01x10 Pa (1000) (9.8) (2.7) 127460 Pa Use the below equati on find the density of salt water ataater Again, this water is open to the atmosphere, so P 1.01x10 Pa Solving this equation for the density of saltwater gives: ataater um altwate when salt water is used, the pressure water- water +4500 Pa = 127460 Pa +4500 Pa = 131960 Pa Substitute the numerical values 131960 Pa 1.01x105 Pa 1 170 kg/m3 altwate The difference in densities is then -1170 kg/m3-1000 kg/m3 = 170 kg/m