1. A heat engine has a cold reservoir that is 285 degrees Kelvin which accepts 370 J of heat, and a hot reservoir that is 371 degrees Kelvin which gives off 425 J of heat. Calculate the maximum and actual efficiencies of this engine. 2. A system that has a total change in entropy of 675 J/K and has received 243 J of heat energy will be at what temperature?

3. Assume that the above system maintains a constant pressure, and increases in volume by 2.5 m 3 while doing this work. What is the pressure of the system?

Atennis player used a tennis racket to hit a tennis ball with a mass of 0.25 kg with a force of 5.25 newtons. how does the force the tennis racket exerted on the tennis ball compare with the force the tennis ball exerted on the tennis racket? a. the force of the tennis racket on the tennis ball is equal in magnitude and opposite in direction to the force the tennis ball exerted on the tennis racket. b. the force of the tennis racket on the tennis ball is equal in magnitude and in the same direction as the force the tennis ball exerted on the tennis racket. c. the force of the tennis racket on the tennis ball is less in magnitude and in the same direction as the force the tennis ball exerted on the tennis racket. d. the force of the tennis racket on the tennis ball is greater in magnitude and opposite in direction as the force the tennis ball exerted on the tennis racket.