57. For the transfer function G (s) H (s) s(s + 1) (s + 0.5) the phase cross-over frequency is
A. 0.5 rad/sec
B. 0.707 rad/sec
C. 1.732 rad/sec
D. 2 rad / sec
58. A linear stable invariant system is forced with an input x (t) = A sin cot x (t) ---> G (s) --> y(t) Under steady-state conditions, the output y(t) of the system will be
A. A sin (cot + 4)), where = tan -I IG(J0))1
B. I G (jw) IA sin [cot + LG (jo))]
C. I G(jo)) I A sin [aot + LG (jw)]
D. AG (jw) sin [an + G (jw)]
59. A unity feedback control system has a forward path transfer function equal to 42.25 s(s + 6.5) The unit step response of this system starting from rest, will have its maximum value at a time equal to
A. 0 sec
B. 0.56 sec
C. 5.6 sec
60. A plant has the following transfer function :G(s) ? (s2 + 0.2s + 1)From a step input it is required that the response settles to within 2% of its final value. The plant setting time is
A. 20 sec.
B. 40 sec.
C. 35 sec
D. 45 sec.
61. The maximum phase shift that can be provided by a lead compensator with transfer function
62. The transfer function of a compensating network is of the form (1 + aTs) . If this (1 + Ts) is a phase-lag network, the value of a should be
A. exactly equal to 0
B. between 0 and 1
C. exactly equal to 1
D. greater than 1.
63. Which one of the following is an example of open-loop system?
A. A windscreen wiper
C. Respiratory system of an animal
D. A system for controlling anti-rocket missiles.
Page 9 of 47