## Sunday, 28 August 2016

### OBJECTIVE QUESTIONS - Longitudinal and Transverse Vibrations

Longitudinal and Transverse Vibrations
Objective type questions

1. 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

2. Longitudinal vibrations are said to occur when the particles of a body moves
(a) Perpendicular to axis
(b) Parallel to its axis
(c) In a circle about the axis

3. When a body is subjected to transverse vibrations, the stress induced in a body will be
(a) Shear stress          (b) Tensile stress          (c) Compressive stress

4. The factor which affects the critical speed of the shaft is
(a) Diametre of the shaft               (b) Span of the shaft
(c) Eccentricity                               (d) All of these

5. The ratio of the maximum displacement of the forced vibration to the deflection due to the static force, is known as
(a) Damping factor               (b) Damping coefficient
(c) Logarithmic decrement  (d) Magnification factor

6. In vibration isolation system, if  ω/ωn is less than Sqare root 2, then for all values of the damping factor, the transmissibility will be
(a) Less than unity (b) Equal to unity (c) Greater than unity (d) Zero

Where ω = Circular frequency of the system in rad/s, and
ωn = Natural circular frequency of vibration of the system in rad/s

7. In vibration isolation system, if ω/ωn is greater than 1, then the phase difference between the transmitted force and the disturbing force is
(a) 0°           (b)  90°
(c) 180°        (d) 270°