Consider a modification of the air-standard otto cycle in which the isentropic compression and expansion processes are each replaced with polytropic processes having n = 1.35. the compression ratio is 12 for the modified cycle. at the beginning of compression, p1 = 1 bar and t1 = 310 k. the maximum temperature during the cycle is 2200 k. determine: (a) the heat transfer and work in kj per kg of air for each process in the modified cycle. (b) the percent thermal efficiency. (c) the mean effective pressure, in bar.

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?