Air expands adiabatically in a piston-cylinder assembly from an initial state where p1 and t1 1000 °r, to a final state where p2 60 lbf/in.2 the process is polytropic with n 1.4. the change in specific internal energy, in btu/lb, can be expressed in terms of temperature change as au (0.171) (72 - t1). determine the final temperature, in r kinetic and potential energy effects can be neglected.

Sally turns on her cellular telephone to speak to her friend who is located thousands of miles away. which of the following best describes how such a telephone is able to transmit and receive information? a. the cellular telephone transmits, receives, and encodes information using only sound waves. b. the cellular telephone transmits, receives, and encodes information using only electromagnetic waves. c. the cellular telephone transmits information by electromagnetic waves to a receiver which then encodes them and produces sound. d. the cellular telephone transmits information by sound waves to a receiver which then encodes them and produces electromagnetic waves.