A man stands on top of a cliff and shouts. He hears the echo on the third clap when
he claps his hand at the rate of two claps
per second. What is the distance between
man & the obstruction, if the velocity of
sound is 320 m/s

When a vertical beam of light passes through a transparent medium, the rate at which its intensity i decreases is proportional to i(t), where t represents the thickness of the medium (in feet). in clear seawater, the intensity 3 feet below the surface is 25% of the initial intensity i0 of the incident beam. what is the intensity of the beam "10" feet below the surface? (give your answer in terms of i0. round any constants or coefficients to five decimal places.)