1)One of the most efficient engines ever built is a coal-fired steam turbine in the Ohio valley, driving an electric generator as it operates between 1870°C and 430°C.
(a) What is its maximum theoretical efficiency?
%
(b) Its actual efficiency is 42.0%. How much mechanical power does the engine deliver if it absorbs 1.4 105 J of energy each second from the hot reservoir?
kW
2) A 70-kg log falls from a height of 28 m into a lake. If the log, the lake, and the air are all at 303 K, find the change in entropy of the Universe during this process.
J/K
