Juanita has done her experiment twenty times, and has gotten the same result every time. what would be the best thing for her to do to increase the validity of her results? a. throw out her results and start over. b. do the experiment twenty more times. c. ask a peer to do the experiment a few times. d. change her variables and do a different experiment.

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.