Approximately how much fencing is needed to enclose a circular pond with a diameter of 12.5 feet?

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?

The charge on an electron is 1.60218 × 10−19 c and its mass is 9.10939 × 10−31 kg. how strong a magnetic field must be experienced by the electron if its path is a circle of radius 5.5 cm? answer in units of t.

A0.750 kg aluminum pan is removed from the stove and plunged into a sink filled with 10.0 kg of water at 293 k. the water temperature quickly rises to 297 k. what was the initial temperature of the aluminum pan? the specific heat of aluminum is ca = 900 j/(kgk) and water is cw = 4190 j/(kgk)