An 8-m-long, uninsulated square duct of cross section 0.2 m x 0.2 m and relative roughness 10^-3 passes through the attic space of a house. hot air enters the duct at 1 atm and 80°c at a volume flow rate of 0.15 m^3 /s. the duct surface is nearly isothermal at 60°c. determine the rate of heat loss from the duct to the attic space and the pressure difference between the inlet and outlet sections of the duct. evaluate air properties at a bulk mean temperature of 80°c. is this a good assumption?

Two technicians are discussing the intake air temperature (iat) sensor. technician a says that the computer uses the iat sensor as a backup to the engine coolant temperature (ect) sensor. technician b says that the powertrain control module (pcm) will subtract the calculated amount of fuel if the air measures hot. who is correct

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.

Slip occurs via two partial dislocations because of (a) the shorter path of the partial dislocation lines; (b) the lower energy state through partial dislocations; (c) the charge balance.