A roller coaster starts at a point 30 m above the bottom of a dip with a speed of 25 m/s. Neglect friction, what will be the speed of the rollercoaster at the top of the next slope, which is 45 m above the bottom of the dip

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.)