A rotary air compressor takes in air (which may be treated as a perfect gas) at a pressure of 1 bar and a temperature of 20°C and compress it adiabatically to a pressure of 6 bar. The isentropic efficiency of the processes is 0.85 and changes in kinetic and potential energy may be neglected. Calculate the specific entropy change of the air. Take R = 0.287 kJ/kg K and C = 1.006 kJ/kg K.

I am attaching both questions for 4 and 5 with the question in the image. thank you. NOTE : So the last person answered this question WITHOUT refencing the answer for whether question 4 or 5 answeres were given, so i am asking for question 5(or the answer for the question that was NOT solved because it was not referenced.) These were the following answers given to me from the last person on bartleby who answered my question without referencing whether it was the answer for question 4 or 5.  1 pass 2 fail 3 fail 4 pass

Question 16 Here is a way we can estimate the distance from the earth to the moon. When the moon is seen at its zenith at a point A on the earth, it is observed to be at the horizon from point B. Points A and B are 6152 miles apart and the radius of the earth is 3960 miles. 20 Earth 0= B a) Calculate the angle in radians. (Round your answer to 5 decimal places.) d= ? v Moon Details b) Estimate the distance from point A to the moon using your angle from part a). (Round your answer to the nearest thousand.) ?

2. Thermal Efficiency a. Planet Express Generating Station in New York, NY uses 8720 Btu of energy to generate each kilowatt hour of electricity. Find its thermal efficiency. Express as a percentage with no decimal point. b. Mystery Shack Generating Station in Gravity Falls, OR has a thermal efficiency of 43%. How many million cubic feet (MMcf) of natural gas are needed to generate 560 megawatt hours of electricity? Round to the nearest hundredth.