The output of an under-damped second-order system with ζ = 0.1 subjected to step-input forcing initially oscillates with a period equal to 1 s until the oscillation dissipates. the same system then is subjected to sinusoidal-input forcing with a frequency equal to 12.62 rad/s. determine the phase lag (in degree) at this frequency.

Which of the following controllers anticipates the future from the slope of errors over time? a)-proportional b)-on/off c)-integral d)-derivative.

An air compression refrigeration system is to have an air pressure of 100 psia in the brine tank and an allowable air temperature increase of 60°f for standard vapor compression cycle temperatures of 77 f entering the expansion cylinder and 14 f entering the compression cylinder, calculate the coefficient of performance a. 2.5 b 3.3 c. 4.0 d. 5.0

Apressure vessel with an r/t 20 cannot be treated as thin walled vessel. a)-trune b)- false