Thel speed of sound in water is 1498 m/s. a sonar signal is sent straight down from a ship at a point just below the water surface, and 2.50 s later reflected signal is detected. how deep is the water

A10nc charge sits at a point in space where the magnitude of the electric field is 1500 n/c. what will the magnitude of the field be if the 10 nc charge is replaced by a 20 nc charge? assume the system is big enough to consider the charges as small test charges.