When a machine member is subjected to torsion, the torsional shear stress set up in the member is

When a body is subjected to biaxial stress i.e. direct stresses ($${\sigma _{\text{x}}}$$) and ($${\sigma _{\text{y}}}$$) in two mutually perpendicular planes accompanied by a simple shear stress ($${\tau _{{\text{xy}}}}$$ ), then maximum shear stress is

A

$$\frac{1}{2}\sqrt {{{\left( {{\sigma _{\text{x}}} - {\sigma _{\text{y}}}} \right)}^2} + 4\tau _{{\text{xy}}}^2} $$

B

$$\frac{1}{2}\sqrt {{{\left( {{\sigma _{\text{x}}} + {\sigma _{\text{y}}}} \right)}^2} + 4\tau _{{\text{xy}}}^2} $$

C

$$\sqrt {{{\left( {{\sigma _{\text{x}}} - {\sigma _{\text{y}}}} \right)}^2} + \tau _{{\text{xy}}}^2} $$

D

$$\sqrt {{{\left( {{\sigma _{\text{x}}} + {\sigma _{\text{y}}}} \right)}^2} + \tau _{{\text{xy}}}^2} $$

When a body is subjected to a direct tensile stress ($${\sigma _{\text{x}}}$$) in one plane accompanied by a simple shear stress ($${\tau _{{\text{xy}}}}$$ ), the maximum shear stress is

A

$$\frac{{{\sigma _{\text{x}}}}}{2} + \frac{1}{2}\sqrt {\sigma _{\text{x}}^2 + 4\tau _{{\text{xy}}}^2} $$

B

$$\frac{{{\sigma _{\text{x}}}}}{2} - \frac{1}{2}\sqrt {\sigma _{\text{x}}^2 + 4\tau _{{\text{xy}}}^2} $$

C

$$\frac{{{\sigma _{\text{x}}}}}{2} + \frac{1}{2}\sqrt {\sigma _{\text{x}}^2 - 4\tau _{{\text{xy}}}^2} $$

D

$$\frac{1}{2}\sqrt {\sigma _{\text{x}}^2 + 4\tau _{{\text{xy}}}^2} $$

When a shaft, is subjected to torsion, the shear stress induced in the shaft varies from

A

Minimum at the center to maximum at the circumference

B

Maximum at the center to minimum at the circumference

C

Zero at the center to maximum at the circumference

D

Maximum at the center to zero at the circumference

The design stress, which is more than the damaging stress, is the least unit stress that will render a member unfit for service before the end of its normal life. The design stress factor or factor of safety indicates the margin between design stress and the __________ stress.

A

Working

B

Damaging

C

Allowable

D

None of these

The strain energy stored in a body due to shear stress, is (where $$\tau $$ = Shear stress, C = Shear modulus and V = Volume of the body)

A

$$\frac{{\tau {\text{V}}}}{{2{\text{C}}}}$$

B

$$\frac{{2{\text{C}}}}{{\tau {\text{V}}}}$$

C

$$\frac{{{\tau ^2}{\text{V}}}}{{2{\text{C}}}}$$

D

$$\frac{{2{\text{C}}}}{{{\tau ^2}{\text{V}}}}$$

When a body is subjected to a direct tensile stress (σ) in one plane, the maximum shear stress is __________ the maximum normal stress.

A

Equal to

B

One-half

C

Two-third

D

Twice

According to maximum shear stress failure criterion, yielding in material occurs, when the maximum shear stress is equal to __________ times the yield stress.

A

0.5

B

2

C

$$\sqrt 2 $$

D

$$\sqrt {\frac{3}{2}} $$

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 shear stress at the center of a circular shaft under torsion is

A

Zero

B

Minimum

C

Maximum

D

Infinity

When a circular beam of diameter d is subjected to a shear force F, the maximum shear stress induced will be

A

$$\frac{{4{\text{F}}}}{{\pi {{\text{d}}^2}}}$$

B

$$\frac{{{\text{6F}}}}{{\pi {{\text{d}}^2}}}$$

C

$$\frac{{{\text{8F}}}}{{\pi {{\text{d}}^2}}}$$

D

$$\frac{{{\text{16F}}}}{{3\pi {{\text{d}}^2}}}$$

When a machine member is subjected to torsion, the torsional shear stress set up in the member is

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