A long copper rod of diameter 2.0 cm is initially at a uniform temperature of 100°C. It is now exposed to an air stream at 4°C with a heat transfer coefficient of 200 W/m2•K. How long would it take for the copper road to cool to an average temperature of 25°C? (Express the answers in seconds.) (Thermal properties of copper: k = 401 W/m·°C, rho = 8933 kg/m3, cp = 0.385 kJ/kg·°C.) s.

see earlier answer

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.