Mechanical Vibration Part-1

The natural frequency of a spring-mass system on earth is N .The natural frequency of this system on the moon is

• N

• 0.408N

• 0.204N

• 0.167N

If the length of the cantilever beam is halved, then natural frequency of the mass M at the end of this, cantilever beam of negligible mass is increased by a factor of

• 2

• 4

• 8

•  $\sqrt{8}$  

A machine of 250 kg mass is supported on springs of total stiffness 100 kN/m. Machine has an unbalanced rotating force of 350 N at speed of 3600 rpm. Assuming a damping factor of 0.15, the value of transmissibility ratio is

• 0.0531

• 0.9922

• 0.0162

• 0.0028

Tags

NGSS.HS-ETS1-3

NGSS.HS-PS2-3

The natural frequency of an undamped vibrating system is 100 rad/s A damper with a damping factor of 0.8 is introduced into the system, The frequency of vibration of the damped system, rad/s, is

• 60

• 75

• 80

• 100

In a spring-mass system, the mass is 0.1 kg and the stiffness of the spring is 1 kN/m. By introducing a damper, the frequency of oscillation is found to be 90% of the original value. What is the damping coefficient of the damper (Ns/m)

• 1.2

• 3.4

• 8.7

• 12

A vibratory system consists of a mass 12.5 kg, a spring of stiffness 1000 N/m, and a dashpot with damping coefficient of 15 Ns/m.

The value of critical damping of the system is (Ns/m)

• 0.223

• 17.88

• 71.4

• 223.6

A vibratory system consists of a mass 12.5 kg, a spring of stiffness 1000 N/m, and a dashpot with damping coefficient of 15 Ns/m.

The value of logarithmic decrement is

• 1.35

• 1.32

• 0.68

• 0.42

The static deflection of a shaft under a flywheel is 4 mm. Take g = 10m/s2 . What is the critical speed in rad/s ?

• 50

• 20

• 10

• 5

 $\frac{\text{d}^2x}{\text{d}t^2}+36\text{x=0}$  is the equation of free vibrations of a system. Its natural frequency is (Rad/s)

• 36

• 6

• 9

• 0

Tags

NGSS.HS-PS4-1

A motion is aperiodic at what value of the damping factor?

• 1 or above

• 0.5

• 0.3

• 0.866