Calculate the efficiency for each machine, then answer the question. Machine A has an input work of 1,000 J and an output work of 250 J.

Machine B has an input work of 500 J and an output work of 350 J.

Machine C has an input work of 200 J and an output work of 150 J.

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.