The ratio of driving tensions in V-belt drives is __________ flat belt drives.

A drives 30 km south. Then he turns right and drives another 30 km. Turning left from here. he drives 20 km. finally turning left, he drives 30 km. How far is A from his starting position?

A

30 km

B

20 km

C

80 km

D

None of above.

The tension on the slack side of the belt is __________ the tension on the tight side of the belt.

A

Equal to

B

Less than

C

Greater than

D

None of these

The stretching in a belt can be controlled by __________ the stress in the belt.

A

Reducing

B

Increasing

C

Both A and B

D

None of these

The capacity of a belt conveyor depends upon two factors. If one is the cross-section of the load, the other is the __________ of the belt.

A

Speed

B

Thickness

C

Length

D

None of these

In a band and block brake, the ratio of tensions on tight side and slack side of the band is (where $$\mu $$ = Coefficient of friction between the blocks and the drum, $$\theta $$ = Semi-angle of each block subtending at the center of drum and n = Number of blocks)

A

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = \mu \theta {\text{n}}$$

B

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\frac{{1 - \mu \tan \theta }}{{1 + \mu \tan \theta }}} \right)^{\text{n}}}$$

C

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\mu \theta } \right)^{\text{n}}}$$

D

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\frac{{1 + \mu \tan \theta }}{{1 - \mu \tan \theta }}} \right)^{\text{n}}}$$

In a band and block brake, the ratio of tensions on the tight and slack sides of band is given by (where $$\mu $$ = Coefficient of friction between the blocks and the drum, $$\theta $$ = Semi-angle of each block subtending at the centre of drum and n = Number of blocks)

A

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_{\text{2}}}}} = \mu \theta \times {\text{n}}$$

B

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\mu \theta } \right)^{\text{n}}}$$

C

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\frac{{1 - \mu \tan \theta }}{{1 + \mu \tan \theta }}} \right)^{\text{n}}}$$

D

$$\frac{{{{\text{T}}_1}}}{{{{\text{T}}_2}}} = {\left( {\frac{{1 + \mu \tan \theta }}{{1 - \mu \tan \theta }}} \right)^{\text{n}}}$$

The power transmitted by a belt is maximum when the maximum tension in the belt is _________ of centrifugal tension.

A

One-third

B

Two-third

C

Double

D

Three times

In multi V-belt transmission, if one of the belt is broken, we have to change the

A

Broken belt

B

Broken belt and its adjacent belts

C

All the belts

D

There is no need of changing any one as remaining belts can take care of transmission of load

A pulley and belt in a belt drive form a

A

Cylindrical pair

B

Turning pair

C

Rolling pair

D

Sliding pair

In a multiple V-belt drive, when a single belt is damaged, it is preferable to change the complete set to

A

Reduce vibration

B

Reduce slip

C

Ensure uniform loading

D

Ensure proper alignment

The ratio of driving tensions in V-belt drives is __________ flat belt drives.

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