Suppose we have a collection of audio sensors that feed into a wireless satellite communications link back to a control center. there are 20 sensors and the acoustic signals they monitor have frequencies up to 500 hz. (a) what sampling rate do we need to ensure that we can accurately reconstruct the acoustic signals at the control center?
(b) if we can have a quantization error up to 0.05% of peak, what number of bits per sample do we need?
(c) based on (a) and (b), what will be the digital data rate (bits per second) needed for each of the 20 sensors?

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false

Aplate clutch has a single pair of mating friction surfaces 250-mm od by 175-mm id. the mean value of the coefficient of friction is 0.30, and the actuating force is 4 kn. a) find the maximum pressure and the torque capacity using the uniform-wear model. b) find the maximum pressure and the torque capacity using the uniform-pressure model.