A4 cm diameter sphere of copper is initially at a temperature of 95 °c. it is placed in a very large water bath at time t- 0. the water bath is initially at a uniform temperature of 25 °c. the heat transfer coefficient is estimated to be 400 watts / (m2 °c). the specific heat of copper is 0.385 joule (gram °c) and its density is approximately 9 gram per cc. estimate the time at which the average temperature of the sphere will be 35 °c.