288. The rate of decay of oscillations is known as

A.Critical damping

B.Damping coefficiera

C.Transmissibility

D.Logarithmic decrement

289. In forced vibrations the magnitude of damping force at resonance equals

A.Inertia force

B.Impressed force

C.Infinity

D.Spring force

290. In steady state forced vibrations, the amplitude of vibrations at resonance is

A.Directly proportional to the damping coefficient

B.Directly proportional to the resonant frequency

C.Inversely proportional to the damping coefficient

D.Inversely proportional to the resonant frequency

291. The ratio of the maximum displacement of the forced vibration to the deflection due to the static force is called

A.Logarithmic decrement

B.Damping coefficient

C.Critical damping coefficient

D.Magnification factor

292. The ratio of the actual damping coefficient to the critical damping coefficient is called

A.Magnification factor

B.Damping factor

C.Logarithmic decrement

D.Transmissibility

293. For steady state forced vibrations, the phase lag nt resonance condition is

A.0?

B.45?

C.90

D.180?.

294. A rotary system having damping coefficient of 50N sec m/rad, when twisted with an angular velocity of 2 rad/sec will experience the damping torque of

A.50 Nm

B.100 Nm

C.25 Nm

D.200 Nm

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