Description : Which of the following instruments measure the amplitude of a vibrating body? (A) Vibrometers (B) Seismometer (C) Both (a) and (b) (D) None of these
Last Answer : (C) Both (a) and (b)
Description : A seismometer is a device used to measure the ___________ of a vibrating body. (A) displacement (B) velocity (C) acceleration (D) all of the above
Last Answer : (A) displacement
Description : The instrument that measures the displacement of a vibrating body is called__________ a. seismometer b. transducer c. accelerometer
Last Answer : a. seismometer
Description : The instruments which are used to measure the ___________ of a vibrating body are called vibration measuring instrument. (A) displacement (B) velocity (C) acceleration (D) all of the above
Last Answer : (D) all of the above
Description : Calculate logarithmic decrement if the amplitude of the vibrating body reduces to half in two cycles A 0.346 B 0.693 C 0.301 D 0.150
Last Answer : A 0.346
Description : The advantage of critical damping is A. That vibrating body come to rest in smallest possible time B. There is no vibration C. That amplitude of vibration is maximum D. The amplitude of vibration is minimum
Last Answer : A. That vibrating body come to rest in smallest possible time
Description : Determine logarithmic decrement, if the amplitude of a vibrating body reduces to 1/6 th in tw cycles. a. 0.223 b. 0.8958 c. 0.3890 d. None of the above
Last Answer : b. 0.8958
Description : In under damped vibrating system, if x 1 and x 2 are the successive values of the amplitude on the same side of the mean position, then the logarithmic decrement is equal to A x 1 /x 2 B log (x 1 /x 2 ) C loge (x 1 /x 2 ) D log (x 1 .x 2 )
Last Answer : C loge (x 1 /x 2 )
Description : A vibrating system having mass 1kg, a spring of stiffness 1000N/m and damping factor of 0.632 and it is put to harmonic excitation of 10N. Find the amplitude at resonance. A 0.079 B 7.9C 0.056 D 0.00791
Last Answer : D 0.00791
Description : In under damped vibrating system, if x 1 and x 2 are the successive values of the C amplitude on the same side of the mean position, then the logarithmic decrement is equal to ( A ) x 1 /x 2 ( B ) log (x 1 /x 2 ) ( C ) loge (x 1 /x 2 ) ( D ) log (x 1 .x 2 )
Last Answer : ( C ) loge (x 1 /x 2 )
Description : In under damped vibrating system, if x1 and x2 are the successive values of the amplitude on the same side of the mean position, then the logarithmic decrement is equal to a) x1/x2 b) log (x1/x2) c) ln (x1/x2) d) log (x1.x2)
Last Answer : c) ln (x1/x2)
Description : In under damped vibrating system, the amplitude of vibration ______. (A) decreases linearly with time (B) increases linearly with time (C) decreases exponentially with time (D) increases exponentially with time
Last Answer : (C) decreases exponentially with time
Description : In under damped vibrating system, if x 1 and x 2 are the successive values of the amplitude on the same side of the mean position, then the logarithmic decrement is equal to a) x 1 /x 2 b) log (x 1 /x 2 )c) loge (x 1 /x 2 ) d) log (x 1 .x 2 )
Last Answer : b) log (x 1 /x 2 )
Description : Vibration measuring instruments are classified on the basis of ____________. (A) contact between the vibrating system and measuring instrument (B) the requirement of power source (C) method of measurements (D) all of the above
Description : The reciprocal of the interval of time by a vibrating body to complete a cycle is called A Period B Frequency C Resonance D None of the mentioned
Last Answer : B Frequency
Description : When no external force is acting on the vibrating body, the vibrations are said to be A. Free Vibrations B. Forced Vibrations C. Loaded Vibrations D. Undamped Vibrations
Last Answer : A. Free Vibrations
Description : When the external force is acting on the vibrating body, the vibrations are said to be A. Natural Vibrations B. Forced Vibrations C. Loaded Vibrations D. Undamped Vibrations
Last Answer : B. Forced Vibrations
Description : The instrument that measures the acceleration of a vibrating body is called___________
Last Answer : Ans- Accelerometer
Description : Which of the following statements is/are true for coulomb damping? 1. Coulomb damping occurs due to friction between two lubricated surfaces2. Damping force is opposite to the direction of motion of vibrating body ... 2, 3 and statement 4 c. Only statement 2 d. All the above statements are true
Last Answer : c. Only statement 2
Description : In vibrometer, the relative motion between the mass and vibrating body is converted into proportional ________. (A) current (B) voltage (C) resistance (D) ampere
Last Answer : (B) voltage
Description : When the torsional pendulum vibrating the observed amplitudes on the same side of neutral axis for successive cycles are found to decay 50% of the initial value determine logarithmic decrement. A 0.065 B 0.006 C 0.693 D 0.5
Last Answer : C 0.693
Description : When the torsional pendulum vibrating, the observed amplitudes on the same side of the neutral axis for successive cycles are found to decay 50% of the initial value determine logarithmic decrement. A 0.065 B 0.006 C 0.693 D 0.5
Description : Calculate the value of critical damping coefficient if a vibrating system has mass of 4kg and stiffness of 100N/m A 20 N-sec/m B 40 N-sec/m C 60 N-sec/m D 80 N-sec/m
Last Answer : B 40 N-sec/m
Description : A system is said to be critically damped if the damping factor for a vibrating system is A Zero B Less than one C One D More than one
Last Answer : C One
Description : The equation of motion for a vibrating system with viscous damping is d 2 x/dt 2 + c/m X dx/dt + s/m X x = 0 If the roots of this equation are real, then the system will be A. over damped B. under damped C. critically damped D. none of the mentioned
Last Answer : A. over damped
Description : When parts of a vibrating system slide on a dry surface, the damping is A. Viscous. B. Coulomb C. Structural D. Eddy current
Last Answer : B. Coulomb
Description : A vibrating machine of 100 kg is mounted on a rubber pad which has stiffness of 500 N/m. Determine force transmitted to the foundation if the unbalanced force 500 N acts on it. The frequency ratio (ω/ω n ) is 1.5 and ξ = 0.5 A. 461.62 N B. 400.23 N C. 450 N D. Insufficient data
Last Answer : A. 461.62 N
Description : In a 2-mass 3 spring vibrating system the two masses each are of 9.8 kg coupling spring is having a stiffness of 3430 N/m whereas the other two springs have each a stiffness of 8820 N/m. The two natural frequencies in rad /sec are A) 10 & 20 B) 20 & 30 C) 30 & 40D) 40 & 50
Last Answer : C) 30 & 40
Description : The rotating shaft or rotor vibrates with excessive lateral vibration at angular speed at which occurs is called as A) rotating speed B) critical speed C) vibrating speed D) None of the above
Last Answer : B) critical speed
Description : Beats phenomenon occurs when a vibrating system is subjected to two different frequencies which are A) Quite different B) Equal C) Slightly different D) Integral multiple of each other
Last Answer : C) Slightly different
Description : The number of degrees of freedom of a vibrating system depends on a. number of masses b. number of masses and degrees of freedom of each mass c. number of coordinates used to describe the position of each mass d. None of the above
Last Answer : b. number of masses and degrees of freedom of each mass
Description : If the damping factor for a vibrating system is unity, then the system will be (A) overdamped (B) underdamped (C) critically damped (D) without vibrations
Last Answer : (C) critically damped
Description : The equation of motion for a vibrating system with viscous damping is d 2 x/dt 2 + c/m X dx/dt + k/m X x = 0 If the roots of this equation are real, then the system will be a) over damped b) under damped c) critically damped d) none of the mentioned Ans:a
Last Answer : a) over damped
Description : When a rigid body is suspended vertically and it oscillates with a small amplitude under the action of the force of gravity, the body is known as * 1 point (A) simple pendulum (B) torsional pendulum (C) compound pendulum (D) second’s pendulum
Last Answer : (C) compound pendulum
Description : When there is a reduction in amplitude over every cycle of vibration, then the body is said to have A Free vibration B Forced vibration C Damped vibration D None of the mentioned
Last Answer : C Damped vibration
Description : When a rigid body is suspended vertically and it oscillates with a small amplitude under the action of the force of gravity, the body is known as A. simple pendulum B. torsional pendulum C. compound pendulum D. second’s pendulum
Last Answer : C. compound pendulum
Description : When there is a reduction in amplitude over every cycle of vibration, then the body is said to have ( A ) Free vibration ( B ) Forced vibration ( C ) Damped vibration ( D ) None of the mentioned
Last Answer : ( C ) Damped vibration
Description : When there is a reduction in amplitude over every cycle of vibration, then the body is said to have a) free vibration b) forced vibration c) damped vibrationd) under damped vibration
Last Answer : c) damped vibration
Description : When a rigid body is suspended vertically and it oscillates with a small amplitude under the action of the force of gravity, the body is known as (A) simple pendulum B) torsional pendulum (C) compound pendulum (D) second’s pendulum
Description : When there is a reduction in amplitude over every cycle of vibration, then the body is said to have a) free vibration b) forced vibration c) damped vibration d) under damped vibration
Description : When there is a reduction in amplitude over every cycle of vibration, then the body is said to have a) free vibration b) forced vibration c) damped vibration d) none of the mentioned
Description : The frame consists of a steel beam welded rigidly to two vertical channels. An eccentric exciter weighing 250 N is attached to the beam, which weighs 10 KN and is used to excite the frame. The unbalance weight of ... ends, magnification factor at resonance is A. 307.5 B. 3.075 C. 30.75 D. 0.3075
Last Answer : C. 30.75
Description : In damped free vibrations, which parameters indicate vibrations? A) Natural frequency B) Rate of decay of amplitude C) Both a. and b. D) None of the above
Last Answer : C) Both a. and b.
Description : In which type of vibrations, amplitude of vibration goes on decreasing every cycle? A) Damped vibrations B) Undamped vibrations C) Both a. and b. D) None of the above
Last Answer : A) Damped vibrations
Description : In damped free vibrations, which parameters indicate vibrations? a. Natural frequency b. Rate of decay of amplitude c. Both a. and b. d. None of the above
Last Answer : c. Both a. and b.
Description : In which type of vibrations, amplitude of vibration goes on decreasing every cycle? a. Damped vibrations b. Undamped vibrations c. Both a. and b. d. None of the above
Last Answer : a. Damped vibrations
Description : In damped vibrations, the amplitude of the resulting vibration gradually reduces. This is due to the reason that an amount of energy is always dissipated to overcome the ________ * 1 point (A) Frictional resistance (B) Work done(C) Fluid pressure (D) Air pressure
Last Answer : (A) Frictional resistance
Description : In steady state forced vibrations, the amplitude of vibrations at resonance is _____________ damping coefficient. A equal to B directly proportional to C inversely proportional to D independent of
Last Answer : C inversely proportional to
Description : What is meant by node point? A. The point at which amplitude of vibration is maximum B. The point at which amplitude of vibration is minimum C. The point at which amplitude of vibration is zero D. None of the above
Last Answer : C. The point at which amplitude of vibration is zero