Q1) An engineer is considering the 4 machines below for laboratory railway track testing. Using present worth analysis, which machine should be selected? MARR is 8% per year.
Estimates Machine A Machine B Machine C Machine D
Initial cost, $ -144,000 -130,000 -155,000 -94,000
AOC, $/year -10,000 -11,100 -15,000 -1,000
Salvage value, $ 2,500 0 5,000 4,400
Life, years 3 6 3 6

Asimple speed reducer is composed of 2 spur gears. the pinion gear has a pitch diameter of 0.75" and 36 teeth while the driven gear has a pitch diameter of 4.0" and 192 teeth. a)-what is the diametral pitch of each gear? b)-if an electric motor rotating ccw at 3000 rpm is coupled to the pinion, what is the rotational speed of the driven gear? c)-if the torque delivered to the pinion is 1 n-m, what is the torque on the driven gear? d)-what is the power transmitted by the gear train?