In ______ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft.

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

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

$$\frac{{0.6253}}{{\sqrt {\delta {\text{S}}} }}$$

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

$$\frac{{0.6253}}{{\sqrt \delta }}$$

The critical speed of a shaft depends upon its

A

Mass

B

Stiffness

C

Mass and stiffness

D

Stiffness and eccentricity

A policy taken with critical illness rider benefit is being assigned. Which type of assignment would suit the intended purpose because if the life insured is diagnosed with a critical illness, he only should receive the critical illness rider claim?

A

Absolute assignment

B

Conditional assignment

C

Loan assignment

D

Collateral assignment

In D.C. machines, the ________ in field mmf results in increase in size and cost of machines.

A

increase

B

decrease

C

either of the above

D

none of the above

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 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

Commercial available medium size machines have a speed range of ______ .

A

200 to 400 r.p.m.

B

600 to 1000 r.p.m.

C

1000 to 1500 r.p.m.

D

2000 to 2500 r.p.m.

In ______ machines, the size of the shaft is decided by the critical speed which depends on the deflection of the shaft.

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