In the context of mechanical systems, what does the term efficiency mean? A.
the factor by which a machine multiplies a force
B.
the ratio of a machine’s power to the force of its input
C.
the rate at which a machine performs work
D.
the rate at which a machine consumes energy
E.
the ratio of the work output of a machine to the work input

Air at a pressure of 1atm and a temperature of 40 c is in parallel flow over the top surface of a flat plate that is heated to a uniform temperature of 120 c. the plate has a length of 0.40m (in the flow direction) and a width of 0.15m. the reynolds number based on the plate length is 50, 000. what is the rate of heat transfer from the plate to the air? if the free stream velocity of the air is doubled and the pressure is increased to 10 atm what is the rate of heat transfer?