The two masses in the atwood's machine shown in the figure are initially at rest at the same height. after they are released, the large mass, m2, falls through a height h and hits the floor, and the small mass, m2, rises through a height h.
part a: find the speed of the masses just before m2 lands, giving your answer in terms of m1, m2, g, and h. assume the ropes and pulley have negligible mass and that friction can be ignored.
part b: evaluate your answer to part a for the case h = 1.7 m , m1 = 3.5 kg , and m2 = 4.3 kg.

People with normal vision cannot focus their eyes underwater if they aren't wearing a face mask or goggles and there is water in contact with their eyes. in a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. 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 2.05cm in front of the eye.)