5. Two friends are 90-m apart and begin to walk towards one another. One friend walks at a rate of 2 m/s as the other walks at 3 m/s. How long
before the two friends come into contact with one another?
(A) 18 s
(C) 755
(B) 7.55
(D) 450 $

With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90