Before the collision, the blue marble is moving from left to right, and it has a velocity of 2m/s. The orange marble is moving at an equal speed, but in the opposite direction what is the velocity of the orange marble before the collision

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