Time Response Analysis MCQ

51. The input-output relationship of a system is given by

$r(t)=2\frac{\mathrm{d^2}c(t) }{\mathrm{d} t^2}+3\frac{\mathrm{d} c(t)}{\mathrm{d} t}+2c(t)$

where r(t) and c(t) are input and output respectively. The transfer function of the system is equal to

  1. $\frac{1}{s^2+s+2}$
  2. $\frac{1}{s^2+3s+2}$
  3. $\frac{2}{s^2+3s+2}$
  4. $\frac{1}{s^2+5s+3}$
Answer
Answer. b

52. Consider the function

$F(s)=\frac{ω}{s^2+ω^2}$

where F(s) = laplace transform of f(t). The final value of f(t) is equal to

  1. infinite
  2. zero
  3. finite constant
  4. a value between -1 and +1
Answer
Answer. d

53. The type number of the control system with

$G(s)H(s)=\frac{K(s+2)}{s(s^2+2s+3)}$

  1. two
  2. one
  3. four
  4. three
Answer
Answer. b

54.  For type 2 system, the steady-state error due to ramp input is equal to

  1. finite constant
  2. zero
  3. indeterminate
  4. infinite
Answer
Answer. b

55. Given a unity feedback system with

$G(s)=\frac{K}{s(s+4)}$

the value of K for damping ratio of 0.5 is

  1. 4
  2. 1
  3. 64
  4. 16
Answer
Answer. d

56. For a unity feedback control system with forward path transfer function $G(s)=\frac{K}{s+5}$. What is error transfer function we(s) used for determination of error coefficients?

  1. $\frac{K}{s+5}$
  2. $\frac{K}{s+K+5}$
  3. $\frac{s+5}{s+K+5}$
  4. $\frac{K(s+5)}{s+K+5}$
Answer
Answer. c

57. For a second-order system, natural frequency of oscillation is 10 rad/s and damping ratio is 0.1. What is 2% settling time?

  1. 10 s
  2. 40 s
  3. 4 s
  4. 0.4 s
Answer
Answer. c

58. The open-loop transfer function for unity feedback system is given by

$\frac{5(1+0.1s)}{s(1+5s)(1+20s)}$

Consider the following statements:

  1. The steady-state error for a step input of magnitude 10 is equal to zero.
  2. The steady-state error for a ramp input of magnitude 10 is 2.
  3. The steady-state error for an acceleration input of magnitude 10 is infinite.

Which of the statements given above are correct?

  1. Only i and ii
  2. Only i and iii
  3. Only ii and iii
  4. i, ii and iii
Answer
Answer. d

59. A particular control system yielded a steady-state error of 0.20 for unit step input. A unit integrator is cascaded to this system and unit ramp input is applied to this modified system. What is the value of steady-state error for this modified system?

  1. 0.10
  2. 0.15
  3. 0.20
  4. 0.25
Answer
Answer. d

60. A system function $N(s)=\frac{V(s)}{I(s)}=\frac{s+3}{4s+5}$

The system is initially at rest. If the excitation i(t) is a unit step, which of the following are the initial and steady-state values of v(t)?

Initial value Steady-state value
a. 0 3/5
b. 1/4 0
c. 3/5 1/4
d. 1/4 3/5
Answer
Answer. d