The function f(t) = 3 cos 5001Tt + 5 cos 8001Tt is sampled at 400 samples per second starting at t = 0.00025 s. What false alias frequencies would you expect in the output?

Apreheater involves the use of condensing steam at 100°c on the inside of a bank of tubes to heat air that enters at 1 atm and 25°c. the air moves at 5 m/s in cross flow over the tubes. each tube is 1 m long and has an outside diameter of 10 mm. what is the minimum value of nl needed to achieve an outlet temperature of t 75 c? what is the corresponding pressure drop across the tube bank?