On a 'wear indicator type ball Joint, what does it mean when the grease fitting boss is flush with the base? OA. The ball Joint requires lubrication
OB. The ball joint should be replaced
OC. The steering knuckle has loosened from the ball Joint
OD. Nothing, this is how they are when new

Air enters a horizontal, constant-diameter heating duct operating at steady state at 290 k, 1 bar, with a volumetric flow rate of 0.25 m°/s, and exits at 325 k, 0.95 bar. the flow area is 0.04 m2. assuming the ideal gas model with k = 1.4 for the air, determine (a) the velocity at the inlet and exit, each in m/s, and (c) the rate of heat transfer, in kw flow rate, in kg/s, (b) the mass kg 0.3