Explain how the cs, us, cr, and ur relate to the end result?

Acompound machine is also called a machine. a. force b. simple c. complex d. directional

Anybody wanna ? (picture included? )

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?