4.
According to an article in the March 1989 issue of Scientific
American, seals are believed to have sophisticated acoustic
transmission and detection systems that are similar to sonar. For
example, mother seals locate their pups by measuring the difference
in sound wave arrival times in air and in water. Given that the
speed of sound Wcan be related to the isentropie derivative of
pressure with respect to density op Estimate how far a mother seal
is from her pup if the time difference between air and water is3
seconds. Air is ideal with C,-7/2R. Air and water temperatures are
about 2 °C. For water under these conditions, the isothermal
compressibility K= 45x10-6 bar-1 and C, ~ C, [1284 m]