Physics—Fluids, Waves, Thermodynamics, and Optics I\'ve provided the answers bel
ID: 1648909 • Letter: P
Question
Physics—Fluids, Waves, Thermodynamics, and Optics
I've provided the answers below, so please if you can please explain how to get to the correct answers, explain througly I will greatly appeciate it!
Answers
18) D 19) D 20) E
18. Conside the plot of an engine cycle drawn in the T-S cycle if it goes from A to B to C?· [Hint Start from dS-T( and U fr an entire cycle.] How much work does the engine do in a S (U/K) 500 400 TA A) 4 kJ B) 3 kJ C) 12 kJ D) 15 kJ E) Need to know how much heat is added during the processes. T (K) 300 600 19. Some amount of a hydrocarbon is combusted to add 3500 J of heat to nitrogen, a diatomic ideal gas. The nitrogen is in a piston that can expand but is kept at atmospheric pressure. How much of the heat is used to expand the gas? A) 500 J. B) 2100 J C) 0J D) 1000 J E) 1400 J 20. Consider the Santa Ana winds that we all know and love/despise. Air from the winter desert, around 10° C at night, descends rapidly, without exchanging heat to the surrounding air. The pressure up in the high desert is 0.8 atm on a day when the Santa Anas begin. What is the temperature of the winds coming in? 7/s 283 × ( K ~ 386 K. B)T=283x( 2/5 K ~ 258 K. C)7-283 x (j)2/T K~266 K. D) T=283 x (j)2/5 K ~ 309 K. E)T=283 × ( 2/7 K ~ 302 K.Explanation / Answer
18)The work done in going from A to C through B will be given by the Area under the graph
W = 1/2 base x altitude
W = 1/2 x (600 - 300) x (500 - 400) = 15000 J = 15 x 10^3 J = 15 kJ
Hence, W = 15 kJ
(D)15 kJ is the correct choice.