The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in

A transverse vibrations
B torsional vibrations
C longitudinal vibrations
D none of the mentioned

Correct Answer: transverse vibrations

The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in transverse vibrations and the stress induced is bending stress.
Bissoy MCQ
#Machine Dynamics #Types of Vibratory Motion and Natural Frequency of Free Longitudinal Vibrations

Related Questions

The natural frequency of free torsional vibrations of a shaft is equal to (where q = Torsional stiffness of the shaft and $$I$$ = Mass moment of inertia of the disc attached at the end of a shaft)
A $$2\pi \sqrt {\frac{{\text{q}}}{I}} $$
B $$2\pi \sqrt {{\text{q}}I} $$
C $$\frac{1}{{2\pi }}\sqrt {\frac{{\text{q}}}{I}} $$
D $$\frac{1}{{2\pi }}$$
The natural frequency of free transverse vibrations due to a point load acting over a simply supported shaft is equal to (where $$\delta $$ = Static deflection of a simply supported shaft due to the point load)
A $$\frac{{0.4985}}{{\sqrt \delta }}$$
B $$\frac{{0.5615}}{{\sqrt \delta }}$$
C $$\frac{{0.571}}{{\sqrt \delta }}$$
D $$\frac{{0.6253}}{{\sqrt \delta }}$$
A semicircular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi circular disc and horizontal surface is µ. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will
A Remain horizontal
B Slant up towards direction of pull
C Slant down towards direction of pull
D None of the above
The natural frequency of free transverse vibrations due to uniformly distributed load acting over a simply supported shaft is (where $$\delta {\text{S}}$$ = Static deflection of simply supported shaft due to uniformly distributed load)
A $$\frac{{0.4985}}{{\sqrt {\delta {\text{S}}} }}$$
B $$\frac{{0.5615}}{{\sqrt {\delta {\text{S}}} }}$$
C $$\frac{{0.571}}{{\sqrt {\delta {\text{S}}} }}$$
D $$\frac{{0.6253}}{{\sqrt {\delta {\text{S}}} }}$$
Two shafts A and B are made of the same material. The diameter of shaft A is twice as that of shaft B. The power transmitted by the shaft A will be __________ of shaft B.
A Twice
B Four times
C Eight times
D Sixteen times
A disc is a spinning with an angular velocity $$\omega $$ rad/s about the axis of spin. The couple applied to the disc causing precession will be (where $$I$$ = Mass moment of inertia of the disc and $$\omega {\text{P}}$$  = Angular velocity of precession of the axis of spin)
A $$\frac{1}{2}I{\omega ^2}$$
B $$I{\omega ^2}$$
C $$\frac{1}{2}I\omega \omega {\text{P}}$$
D $$I\omega \omega {\text{P}}$$
The critical speed of a shaft in revolution per second is __________ as that of natural frequency of transverse vibration.
A Same
B Different
C Unpredictable
D None of these
In ______ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft.
A small
B medium
C large
D any of the above
The radius of a friction circle for a shaft rotating inside a bearing is (where r = Radius of shaft and $$\tan \varphi $$  = Coefficient of friction between the shaft and bearing)
A $${\text{r}}\sin \varphi $$
B $${\text{r}}\cos \varphi $$
C $${\text{r}}\tan \varphi $$
D $$\frac{{\text{r}}}{2}\cos \varphi $$
The product of the tangential force acting on the shaft and its distance from the axis of the shaft (i.e. radius of shaft) is known as
A Bending moment
B Twisting moment
C Torsional rigidity
D Flexural rigidity

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