A stream of air (stream 1) at 60°F, 1 atm, 30% relative humidity is mixed adiabatically with a stream of air (stream 2) at 90°F, 1 atm, 80% relative humidity. A single stream (stream 3) exits the mixing chamber at temperature T3 and 1 atm. Assume steady state and ignore kinetic and potential energy effects.

Letting r denote the ratio of dry air mass flow rates m˙a1/m˙a2 determine T3, in °F, for r = 0.1

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Abrake has a normal braking torque of 2.8 kip in and heat-dissipating cast-iron surfaces whose mass is 40 lbm. suppose a load is brought to rest in 8.0 s from an initial angular speed of 1600 rev/min using the normal braking torque; estimate the temperature rise of the heat dissipating surfaces.

Which of the following controllers anticipates the future from the slope of errors over time? a)-proportional b)-on/off c)-integral d)-derivative.