A steel beam is rotated in a horizontal plane to provide the centripetal acceleration for training pilots. If the pilot sits 3.0 m from the center of rotation, at what speed must he rotate to experience a horizontal centripetal acceleration of 72 m/s2 ? A. 24 m/s
B. 14.7 m/s
C. 216 m/s
D. 23.5 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.)