Suppose two initial vectors intersect at a right angle and
form a resultant vector. the magnitudes of one initial
vector, a, and the resultant vector, r, are given.
which formula can be used to find the magnitude of the
other initial vector, b?
o bar
obr+ a
obar
obra?

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.)