Deck 1: Vibrations and Damping in Mechanical Systems

Question 1

Which type of vibrations are also known as transient vibrations?

A)Undamped vibrations
B)Damped vibrations
C)Torsional vibrations
D)Transverse vibrations

Answer 1

Damped vibrations

Question 2

During transverse vibrations, shaft is subjected to which type of stresses?

A)Tensile stresses
B)Torsional shear stress
C)Bending stresses
D)All of the above

Answer 2

Bending stresses

Question 3

What are deterministic vibrations?

A)Vibrations caused due to known exciting force
B)Vibrations caused due to unknown exciting force
C)Vibrations which are aperiodic in nature
D)None of the above

Answer 3

Vibrations caused due to known exciting force

Question 4

Which of the following vibrations are classified according to magnitude of actuating force?

A)Torsional vibrations
B)Deterministic vibrations
C)Transverse vibrations
D)All of the above

Question 5

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

Question 6

The resonant frequency of a mass-spring system depends upon ________

A)stiffness
B)surface density
C)depth of air space
D)all of the above

Question 7

Calculate equivalent stiffness of the spring for the system shown below, which has spring stiffness of 3000 N/m

A)1000 N/m
B)2250 N/m
C)2000 N/m
D)None of the above

Question 8

Which of the following is incorrect regarding inertia force?

A)Imaginary force
B)Acts upon a rigid body
C)Brings the body to equilibrium
D)Same direction as of accelerating force

Question 9

D-Alembert's principle is used for which of the following?

A)Change static problem into a dynamic problem
B)Change dynamic problem to static problem
C)To calculate moment of inertia of rigid bodies
D)To calculate angular momentum of a system of masses

Question 10

Determine logarithmic decrement, if the amplitude of a vibrating body reduces to 1/6th in two cycles.

A)0.223
B)0.8958
C)0.389
D)None of the above

Question 11

Calculate logarithmic decrement if damping factor is 0.33.

A)1.36
B)3.23
C)5.16
D)2.19

Question 12

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

Question 13

What is meant by critical damping coefficient?

A)Frequency of damped free vibrations is less than zero
B)The motion is aperiodic in nature
C)Both a. and b.
D)None of the above

Question 14

Which of the following relations is true for viscous damping?

A)Force ? relative displacement
B)Force ? relative velocity
C)Force ? (1 / relative velocity)
D)None of the above

Question 15

Which among the following is the value of static deflection (?) for a fixed beam with central point load?

A)(Wl3) /(192 EI)
B)(Wl2) /(192 EI)
C)(Wl3) /(384 EI)
D)None of the above

Question 16

According to which method, maximum kinetic energy at mean position is equal to maximum potential energy at extreme position?

A)Energy method
B)Rayleigh's method
C)Equilibrium method
D)All of the above

Question 17

The motion of a system executing harmonic motion with one natural frequency is known as _______

A)principal mode of vibration
B)natural mode of vibration
C)both a. and b.
D)none of the above

Question 18

Fluid resistance causes damping which is known as ______

A)Resistance damping
B)Fluid damping
C)Viscous damping
D)Liquid damping

Question 19

In which direction does the accelerating force acts?

A)Opposite to the motion
B)Along the motion
C)Perpendicular to motion
D)Variable

Question 20

The time interval after which the motion is repeated itself is known as ___________ .

A)Time period
B)Cycle
C)Frequency
D)Isolation

Question 21

Frequency of vibrations is usually expressed in

A)Number of cycles per hour
B)Number of cycles per minute
C)Number of cycles per second
D)None of these

Question 22

The motion completed during one time period is known as _______.

A)Period of vibration
B)Cycle
C)Frequency
D)All of the above

Question 23

Which of the following is a type of free vibration?

A)Longitudinal vibrations
B)Transverse vibrations
C)Torsional vibrations
D)A, B and C

Question 24

In a spring-mass system, which of the following force is not considered?

A)Spring force
B)Damping force
C)Accelerating force
D)A and B

Question 25

The periodic time is given by _______.

A)? / 2 ?
B)2 ? / ?
C)2 ? × ?
D)?/?