6a) a sound wave in a fresh water lake takes 4 s to
return to the surface of the lake. how deep is the
lake at that point?

The slope of a velocity time graph over any interval of time gives the during that interval

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.)

How do the kidneys affect homeostasis