Because the velocity of an object depends on 7. as well as 8. the velocity of an object can change even as the 9. of the object remains constant. Imagine race cars going around an oval track. Even if their 10. remains constant, their velocity changes because the 11. of their motion is changing. If a car is traveling on a street and slows down, its speed 12. and the car has negative 13. Then the car speeds up, giving it positive 14. When the car was slowing down, the 15. was in the opposite 16. of the 17. To calculate a change in velocity, subtract the 18. from the If the direction of motion does not change and the object moves in a straight line, the change in velocity is the same as the change in 20. 19.​

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.)