6.58 In World War II, voice radio scramblers used modulation schemes to distort a signal so that enemy forces could not understand it unless it was demodulated properly. In one scheme, a signal x (t), bandlimited to 4 kHz, is modulated to generate an output signal (a) Plot the range of the spectrum of y(t). (b) Describe why the scrambled signal's spectrum is ''distorted.'' (c) Show that x(t) can be recovered from y(t) using

Aflywheel accelerates for 5 seconds at 2 rad/s2 from a speed of 20 rpm. determine the total number of revolutions of the flywheel during the period of its acceleration. a.5.65 b.8.43 c. 723 d.6.86

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater