Three charged balls of fluff are nailed down to the table at coordinates (0.30 m, 0), (0, 0.10 m), and (0, 0). They have charges 6.0, -1.0, and 5.0 nanocoulombs. How large
is the force on the charge at the origin due to the other charges? (b) What direction is it
in? (c) If you vacuumed up the charge at the origin to get rid of it, is there still an electric
field there? What is its magnitude and direction?

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.)