A 3-ft-diameter duct is used to carry ventilating air ( , ) into a vehicular tunnel at a rate of 11000 ft3/min. Tests show that the pressure drop is 1.2 in. of water per 1500 ft of duct. What is (a) the value of the friction factor for this duct and (b) the approximate size of the equivalent roughness of the surface of the duct

Apiping systems consists of 6 m of 6-std type k and 12 m of 4-std type k, both drawn copper tubing. the system conveys ethylene glycol at a rate of 0.013 m3/s. the pressure drop across the system is to be calculated. there are two 90° elbows in the 6-in pipe, a reduction from the 6-in pipe to the 4-in pipe and four 90° elbows in the 4-in pipe. all fittings are soldered (same as flanged) and regular. the inlet and outlet of the system are at the same height.