(a) What is the best coefficient of performance for a refrigerator that cools an environment at 30.0C and has heat transfer to another environment at 45.0C ? (b) How much work in joules must be done for a heat transfer of 4186 kJ from the cold environment? (c) What is the cost of doing this if the work costs 10.0 cents per 3.60106 J (a kilowatthour)? (d) How many kJ of heat transfer occurs into the warm environment? (e) Discuss what type of refrigerator might operate between these temperatures.
Chapter 1 Introduction Physics o The study of nature The Domains of Physics o Microscopic Domain The domain of atoms, molecules, electrons, protons, pion and mesons, etc. Extreme small in mass Uncertainty of physical properties Unpredictable behavior o Macroscopic Domain The domain of man, house, car, ball, even a planet Daily life experiences Physics experienced on earth Governed by gravity, Newton's Laws (orbit) Predictable behavior o Galactic Domain The domain of galaxies and their clusters characterized by huge masses and high velocities Black holes Relativity Uncertainty of physical properties Three Fundamental Quantities o Length The spatial distance between two points o Mass Measure of an object's resistance to a change in its motion (Inertia) Different from weight! Mass has no direction, therefore it is a Scalar Quantity o Time Is realized by change All other physical quantities can be constructed from these three fundamental quantities o Example: length Speed or Velocity is a quantity