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 w can be related to the isentropic derivative of pressure with respect to density estimate how far a mother seal is from her pup if the time difference between air and water is 3 seconds. air can be assumed ideal with cp = 7/2r. air and water temperatures are about 2 °c. for water under these conditions, the isothermal compressibility κt = 45×10-6 bar-1 and cp ≈ cv

To understand the electric potential and electric field of a point charge in three dimensions consider a positive point charge q, located at the origin of three-dimensional space. throughout this problem, use k in place of 14? ? 0. part adue to symmetry, the electric field of a point charge at the origin must point from the origin. answer in one word. part bfind e(r), the magnitude of the electric field at distance r from the point charge q. express your answer in terms of r, k, and q. part cfind v(r), the electric potential at distance rfrom the point charge q. express your answer in terms of r, k, and q part dwhich of the following is the correct relationship between the magnitude of a radial electric field and its associated electric potential ? more than one answer may be correct for the particular case of a point charge at the origin, but you should choose the correct general relationship. a)e(r)=dv(r)drb)e(r)=v(r)rc)e(r)=? dv(r)drd)e(r)=? v(r)r