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

D. infinity

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

A. 15?

B. 30?

C. 45?

D. 60?

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

B. Aqualung

C. Respiratory system of an animal

D. A system for controlling anti-rocket missiles.

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