An oil bath maintained at 40°C with a convective coefficient 500 W/m2·K is used to quench stainless steel spherical ball bearings ( 25 W/m·K, 4.85 x 10-6 m2/s) in order to harden them. Consider a ball bearing of uniform temperature 850°C and a diameter of 40 mm. How long, in seconds, will it take for the surface temperature of the sphere to reach 100°C? What is the corresponding center temperature, in °C?

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length (in m) of a column of water 1.45 km high for a temperature increase of 1.12°c. assume the column is not free to expand sideways. as a model of the ocean, that is a reasonable approximation, as only parts of the ocean very close to