A long slender solid cylindrical rod made of copper is 2 cm in diameter. It is taken out of a liquid nitrogen bath at 77 K and exposed to a stream of warm air at a temperature of 50 C. Neglect internal temperature gradients find the time taken by the rod to heat up to a temperature of 10 C if the surface heat transfer coefficient is 20 W/m^2K. For copper, take k=330 W/mK and a-95*10^-6 m^2/s.