Until a train is a safe distance from the station it must travel at 5 m/s. Once the train is on open track it can speed up
to 45 m/s. If it takes a train 8 seconds to reach 45 m/s, what is the acceleration of the train? (Round your answer to
the nearest whole number.)
A• 4 m/s2
B• 5 m/s²
C• 6 m/s2
D• 7 m/s2

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. what should be the radius of curvature of the cornea such that the image of an object 40.0 cm from the cornea’s vertex is focused on the retina?