A 2.4 kg block slides along a frictionless surface at 1.3 m/s . A second block, sliding at a faster 4.4 m/s , collides with the first from behind and sticks to it. The final velocity of the combined blocks is 2.3 m/s . What was the mass of the second block?

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.)