A25-cm-diameter stainless steel ball (rho = 8055 kg/m3, cp = 480 j/kg·°c) is removed from the oven at a uniform temperature of 300 °c. the ball is then subjected to the flow of air at 1 atm pressure and 25 °c with a velocity of 3 m/s. the surface temperature of the ball eventually drops to 200 °c. determine the average convection heat transfer coefficient during this cooling process. estimate the average rate of heat transfer.

Two flowing streams of argon gas are adiabatically mixed to form a single flow/stream. one stream is 1.5 kg/s at 400 kpa and 200 c while the second stream is 2kg/s at 500 kpa and 100 ? . it is stated that the exit state of the mixed single flow of argon gas is 150 c and 300 kpa. assuming there is no work output or input during the mixing process, does this process violate either the first or the second law or both? explain and state all your assumptions.

Fluids at rest possess no flow energy. a)- true b)- false

Which of the following ziegler nichols tuning methods the response of the controller to a step input should exhibit an s-shaped curve? a)-open loop mode b)-closed loop mode c)-both modes (open & closed) d)-none of the modes (open & closed)