Kyle and Keion balanced on a seesaw. Kyle's weight is 500 N and Keion weight is 300 N. The seesaw is made of a uniform plank of weight 800 N which is 4 m
long, pivoted at its centre.
By taking moments about the pivot, calculate the distance, that Keion must sit
from the pivot to balance the plank if Kyle sits I m from one end of the plank.

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.)