Explain the difference between alternating (ac) and direct current (dc)

9.98 kg of r-134a at 300 kpa fills a rigid container whose volume is 14 l. determine the temperature and total enthalpy in the container. the container is now heated until the pressure is 600 kpa. determine the temperature and total enthalpy when the heating is completed. use data from the steam tables.

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s.part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.

Employer informs its employees that it will hold a substantial cash prize drawing for each work group at the end of each month in which no employee in the work group sustains a lost-time injury. tyra reports an injury that she sustained while operating a mechanical power press. tyra did not violate any employer safety rules when she sustained her injury. tyra’s injury requires her to miss work for two days. her employer cancels the cash prize drawing for that month for tyra’s work group because of tyra’s lost-time injury. did the employer misuse an incentive program to retaliate against tyra?