21. According to law of transmissibility of forces, effect of force acting on the body is
- different at different points of the body
- minimum when it acts at centre of gravity of the body
- maximum when it acts at centre of gravity of the body
- same at every point in its line of action
22. In viscous damping, the damping force is _________ velocity of vibrating body.
- proportional to
- inversely proportional to
- square of
- cube of
23. When will the resonance occur for an underdamped harmonic oscillator?
- When excitation frequency is greater than the undamped natural frequency
- When excitation frequency is less than undamped natural frequency
- When excitation frequency is equal to undamped natural frequency
- Never occurs
24. Though vibration cannot be eliminated completely, it can be suppressed to a greater extent using
- Damper
- Accumulator
- Receiver
- Reducer
25. If there is a gradual reduction in amplitude of vibration with time, the body is said to be in
- Free vibration
- Forced vibration
- Damped vibration
- Undamped vibration
26. Natural frequency of a system is due to
- free vibration
- forced vibrations
- resonance
- damping
27. Which of the following purposes is served by critical damping?
- It provides basis of determining critical damping
- It predicts nature of vibration
- It provides a measure of the relative amount of damping in a system.
- It enables measurement of damping.
28. The system in which the amplitude of vibration decreases with time and ratio of amplitude of successive oscillate being constant is known as
- Critically damped system
- Underdamped system
- Undamped system
- Overdamped system
29. Whirling speed of a shaft coincides with the natural frequency of its
- Longitudinal vibration
- Transverse vibration
- Torsional vibration
- Coupled bending torsional vibration
30. Damping force per unit velocity is known as
- Damping factor
- Damping coefficient
- Logarithmic decrement
- Stiffness of the spring