The aforementioned five message signals are modulated by a carrier, c(t) = 2 cos(1000πt). Please plot five modulated signals, mk(t)c(t) s. t. k ∈ {1, 2, 3, 4, 5}, in the time domain. Further, please plot the corresponding five spectra in the frequency domain. Consider the both cases of amplitude modulation (AM) schemes.(a) Double-sideband suppressed carrier (DSB-SC) AM (b) Single-sideband (SSB)-SC AM, in particular, focusing on the upper-sideband (USB) AM (c) m4(t) = 11(40.5) (d) m5(t) = 4(4-05)

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?

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2

Hydraulic fluid with a sg. of 0.78 is flowing through a 1.5 in. i.d. pipe at 58 gal/min. the fluid has an absolute viscosity of 11.8 x 105 lbf-sec/ft2. is the flow laminar, turbulent or within the critical range? give both a numerical reynolds number and a term answer.