Theory of Machines

31. Creep in belt drive is due to

1. material of the pulley
2. material of the belt
3. larger size of the driver pulley
4. uneven extensions and contractions due to varying tension
5. expansion of belt.

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32. Cross head and guides form a

1. lower pair
2. higher pair
3. turning pair
4. rolling pair
5. sliding pair.

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33. Crowning on pulleys helps

1. in increasing velocity ratio
2. in decreasing the slip of the belt
3. for automatic adjustment of belt posi-tion so that belt runs centrally
4. increase belt and pulley life
5. none of the above.

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34. Cylindrical cams can be classified as

1. circular
2. tangent
3. reciprocating
4. all of the above
5. none of the above.

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35. Davis steering gear consists of

1. sliding pairs
2. turning pairs
3. rolling pairs
4. higher pairs
5. lower pairs.

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36. Elements of pairs held together mechanically is known as

1. closed pair
2. open pair
3. mechanical pair
4. rolling pair
5. none of the above.

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37. Flexible coupling is used because

1. it is easy to disassemble
2. it is easy to engage and disengage
3. it transmits shocks gradually
4. it prevents shock transmission and eliminates stress reversals
5. it increases shaft life.

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38. For a kinematic chain to be considered as mechanism

1. two links should be fixed
2. one link should be fixed
3. none of the links should be fixed
4. there is no such criterion
5. none of the above.

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39. For fluctuating loads, welsuited bearing is

1. ball bearing
2. roller bearing
3. needle roller bearing
4. thrust bearing
5. sleeve bearing.

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40. For S.H.M. cam, the acceleration of the follower at the ends of the stroke and aimidstroke respectively, is

1. maximum and zero
2. zero and maximum
3. minimum and maximum
4. zero and minimum
5. maximum and minimum.

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