1.  One January morning in 1943, a warm chinook wind rapidly raised the temperature in Spearfish, South Dakota, from below freezing to +12.0 °C. As the chinook died away, the temperature fell to -20.0 °C in 27.0 minutes. Suppose that a 19-m aluminum flagpole were subjected to this temperature change. Estimate the average speed at which its height would decrease. 2.  Sirius B is a white star that has a surface temperature (in kelvins) that is four times that of our sun. Sirius B radiates only 0.040 times the power radiated by the sun. Our sun has a radius of $6.96$*$10^{8}$ $m$. Assuming that Sirius B has the same emissivity as the sun, find the radius of Sirius B.