McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 1. |
The uniform wear conditions are used_____. |
| A. | for maximum power to be transmitted |
| B. | for safe design of clutches |
| C. | for safe design bearing |
| D. | for overcoming the frictional torque |
| Answer» B. for safe design of clutches | |
| 2. |
The uniform Pressure conditions are used_____. |
| A. | for maximum power to be transmitted |
| B. | for safe design of clutches |
| C. | for safe design bearing |
| D. | for overcoming the frictional torque |
| Answer» C. for safe design bearing | |
| 3. |
For safe design of bearing, we assume____. |
| A. | maximum power to be transmitted |
| B. | safe design of clutches |
| C. | safe design bearing |
| D. | overcoming the frictional torque |
| Answer» A. maximum power to be transmitted | |
| 4. |
For safe design of clutches, we assume____. |
| A. | uniform pressure conditions |
| B. | uniform wear condition |
| C. | neither uniform pressure nor uniform wear |
| D. | all of the above |
| Answer» B. uniform wear condition | |
| 5. |
According to uniform wear theory____. Where ,w=Angular velocity of shaft, r=radius of shaft, W=Axial lead on shaft |
| A. | p.w=constant |
| B. | p.r=constant |
| C. | p.w=constant |
| D. | p.t=constant |
| Answer» B. p.r=constant | |
| 6. |
In case of foot step bearing, the frictional force under the conditions of uniform pressure may be assumed to be acting at____. |
| A. | r |
| B. | (1/2).r |
| C. | (3/2).r |
| D. | (2/3)r |
| Answer» D. (2/3)r | |
| 7. |
In case of foot step bearing, the frictional force under the conditions of uniform wear may be assumed to be acting at____. |
| A. | r |
| B. | (1/2).r |
| C. | (3/2).r |
| D. | (2/3).r |
| Answer» B. (1/2).r | |
| 8. |
The ratio of friction torque for uniform pressure to uniform wear for the same dimensions and load is _______. |
| A. | >1 |
| B. | 1 |
| C. | <1 |
| D. | (1/2) |
| Answer» A. >1 | |
| 9. |
Torque required to overcome the friction between shaft and bearing surface in case of multiple flat collar bearing is ___________. |
| A. | independent on of collars |
| B. | dependent on radius of collar |
| C. | dependent of no of collars |
| D. | none of above |
| Answer» A. independent on of collars | |
| 10. |
In case of flat pivot bearing,the rubbing velocity is _________. |
| A. | maximum at the center of the contact area |
| B. | zero at the center and maximum at the outer radius |
| C. | uniform throughout the contact area |
| D. | zero at the outer radius |
| Answer» B. zero at the center and maximum at the outer radius | |
| 11. |
The rate of wearing in case of flat pivot bearing is ______. |
| A. | inversely proportional to the pressure intensity |
| B. | directly proportional to the rubbing velocity |
| C. | directly proportionl to the pressure intensity |
| D. | both (b) and (c ) |
| Answer» D. both (b) and (c ) | |
| 12. |
For calculating the friction power for bearing, the assumptions made in practice are_____. |
| A. | the rate of wearing at the surface is uniform |
| B. | the rubbing velocity is constant |
| C. | the pressure intensity is uniform |
| D. | (a) and (c ) only |
| Answer» D. (a) and (c ) only | |
| 13. |
In case of flat pivot bearing the frictional torque transmitted for uniform pressure as compared to the frictional torque transmitted for uniform wear_____. |
| A. | is more |
| B. | is less |
| C. | is constant |
| D. | may be more or less |
| Answer» A. is more | |
| 14. |
The ratio of friction torque transmitted for uniform pressure to frictional torque transmitted for uniform wear in case of flat pivot, is equal to_______. |
| A. | (1/3) |
| B. | (2/3) |
| C. | 1 |
| D. | (4/3) |
| Answer» D. (4/3) | |
| 15. |
When the axial load carried by the shaft in case of flat collar bearing, is large; a number of collars are provided on the shaft. This is done____. |
| A. | to reduce the frictional torque |
| B. | to increase the frictional torque |
| C. | to reduce the intensity of pressure |
| D. | to increse the intensity of pressure |
| Answer» C. to reduce the intensity of pressure | |
| 16. |
Choose the correct statement regarding the safe design of a bearing. |
| A. | when horse power lost in friction is to be determined, uniform rate of wear is assumed |
| B. | when horse power transmitted is to be determined, uniform pressure is assumed |
| C. | when horse power lost in friction is to be determined, uniform pressure is assumed and when horse power transmitted is to be determined, uniform wear is assumed |
| D. | none of the above |
| Answer» C. when horse power lost in friction is to be determined, uniform pressure is assumed and when horse power transmitted is to be determined, uniform wear is assumed | |
| 17. |
For uniform pressure the ratio of frictional torque for a flat collar bearing to the frictional torque for conical collar bearing is equal to____. Where ϴ=semi-angle of the cone |
| A. | 1.33 |
| B. | 1 |
| C. | sinϴ |
| D. | cosϴ |
| Answer» C. sinϴ | |
| 18. |
For uniform wear, the ratio of frictional torque for a flat collar bearing to the frictional torque for conical collar bearing is equal to____. Where ϴ=semi-angle of the cone |
| A. | 1.33 |
| B. | 1 |
| C. | sinϴ |
| D. | cosϴ |
| Answer» C. sinϴ | |
| 19. |
The ratio of frictional torque for a conical collar bearing to that for flat collar bearing is proportional to____. Where ϴ=semi-angle of the cone |
| A. | sinϴ |
| B. | cosϴ |
| C. | tanϴ |
| D. | 1/sinϴ |
| Answer» D. 1/sinϴ | |
| 20. |
For flat and conical pivots, the ratio of friction torque with uniform wear to friction torque with uniform pressure is ____. |
| A. | (2/3) |
| B. | (3/2) |
| C. | (4/3) |
| D. | (3/4) |
| Answer» D. (3/4) | |
| 21. |
The ratio of frictional torque produced for uniform wear to frictional torque produced for uniform pressure is ____. |
| A. | (3/4) |
| B. | (4/3) |
| C. | (2/3) |
| D. | 1 |
| Answer» A. (3/4) | |
| 22. |
The frictional torque for the same diameter in a conical bearing is ____. |
| A. | more |
| B. | less |
| C. | equal |
| D. | may be more or less |
| Answer» A. more | |
| 23. |
The frictional torque transmitted by a conical bearing is ____. |
| A. | less than that of flat collar bearing |
| B. | equal to that of flat collar bearing |
| C. | more than that of flat collar bearing |
| D. | none of the above |
| Answer» C. more than that of flat collar bearing | |
| 24. |
The frictional torque produced due to friction for same shaft diameter, in conical bearing is____. |
| A. | less than that for flat collar bearing |
| B. | equal to that for flat collar bearing |
| C. | more than that for flat collar bearing |
| D. | may be more or less depending upon cone angle |
| Answer» C. more than that for flat collar bearing | |
| 25. |
Choose the wrong statement |
| A. | the frictional torque transmitted by a shaft fitted with a large number of collars is the same as transmitted by a shaft with one collar |
| B. | the frictional force for uniform pressure, in case of a flat pivot bearing, can be assumed to be acting at a distance of two-thirds of the radius of the shaft from the axis of shaft. |
| C. | when horse power lost in friction is to be determined, uniform pressure is assumed for safe design of bearing |
| D. | the frictional force for uniform pressure, in case of a flat collar pivot bearing, can be assumed to be acting at a distance of half of the sum of internal and external radii of the shaft |
| Answer» D. the frictional force for uniform pressure, in case of a flat collar pivot bearing, can be assumed to be acting at a distance of half of the sum of internal and external radii of the shaft | |
| 26. |
The ratio of frictional torque produced for uniform wear to that for uniform pressure is ____. |
| A. | 1 |
| B. | (2/3) |
| C. | (4/3) |
| D. | (3/4) |
| Answer» D. (3/4) | |
| 27. |
In case of pivot bearing the rate of wear is _____. |
| A. | maximum at the center of the contact area |
| B. | zero at the center of contact |
| C. | uniform throughout the contact area |
| D. | zero at the maximum radius of the contact area |
| Answer» B. zero at the center of contact | |
| 28. |
The number of collars are provided to carry a fixed axial force in a flat collar bearing _______. |
| A. | to increase torque |
| B. | to decrease torque |
| C. | to decrease intensity of pressure |
| D. | to decrease intensity of pressure |
| Answer» C. to decrease intensity of pressure | |
| 29. |
In flat pivot bearing the total moment of friction force______. |
| A. | for uniform wear is greater than that for uniform pressure |
| B. | for uniform wear is less than that for uniform pressure |
| C. | for uniform wear is equal to that for uniform pressure |
| D. | for uniform wear may be more or less and cannot be predicted |
| Answer» B. for uniform wear is less than that for uniform pressure | |
| 30. |
To be safe side in the design, the unform pressure and uniform wear is assumed respectively_____. |
| A. | for power transmitted by friction and power lost due to friction |
| B. | for power lost due to friction and power transmitted by friction |
| C. | for torque transmitted by friction and friction torque overcome |
| D. | none of the above |
| Answer» B. for power lost due to friction and power transmitted by friction | |
| 31. |
Choose the correct statement for safe design. |
| A. | for power lost in friction uniform wear is assumed |
| B. | for power lost in friction uniform pressure is assumed |
| C. | for power transmitted due to friction uniform pressure is assumed |
| D. | for power transmitted due to friction or lost in friction uniform wear is assuned |
| Answer» B. for power lost in friction uniform pressure is assumed | |
| 32. |
Choose the correct statement for safe design. |
| A. | for power transmitted by friction uniform wear is assumed |
| B. | for power transmitted by friction uniform pressure is assumed |
| C. | for power lost in friction and power transmitted uniform wear is assumed |
| D. | power lost in friction and power transmitted uniform pressure is assuned |
| Answer» A. for power transmitted by friction uniform wear is assumed | |
| 33. |
The purpose of providing multiple collars on a flat collar pivot bearing is to ____. |
| A. | establish self sustaining bearing conditions |
| B. | increase the frictional resistance |
| C. | distribute the axial load because of limiting bearing pressure on bearing |
| D. | increase the power absorbed by the bearing |
| Answer» C. distribute the axial load because of limiting bearing pressure on bearing | |
| 34. |
In a multi-collared thrust bearing consisting of 'n' collars and subjected to axial load W, load sheared by each collar is _______. |
| A. | w |
| B. | w/n |
| C. | w/(n-1) |
| D. | none of these |
| Answer» B. w/n | |
| 35. |
A flat foot step bearing 20 cm in diameter supports a load of 2500 kgf. The shaft is running at 420 rpm and the co-efficient is 0.09. The frictional torque, for uniform pressure, will be equal to ___. |
| A. | 11.25 n-m |
| B. | 15 n-m |
| C. | 18.50 n-m |
| D. | 20.0 n-m |
| Answer» B. 15 n-m | |
| 36. |
A flat foot step bearing 20 cm in diameter supports a load of 2500 kgf. The shaft is running at 420 rpm and the co-efficient is 0.09. The frictional torque, for uniform wear, will be equal to ___. |
| A. | 11.25 n-m |
| B. | 15 n-m |
| C. | 18.50 n-m |
| D. | 20.0 n-m |
| Answer» A. 11.25 n-m | |
| 37. |
A flat foot step bearing 20 cm in diameter supports a load of 2500 kgf. The shaft is running at 420 rpm and the co-efficient is 0.09. The power lost in overcoming friction at the bearing, will be equal to ___. |
| A. | 650 watt |
| B. | 880 watt |
| C. | 659.7 watt |
| D. | 680.20 watt |
| Answer» C. 659.7 watt | |
| 38. |
flat foot step bearing 20 cm in diameter supports a load of 2500 kgf. The shaft is running at 420 rpm and the co-efficient is 0.09. The power transmitted by the friction between the surface, will be equal to ___. |
| A. | 493.875 watt |
| B. | 880 watt |
| C. | 659.7 watt |
| D. | 680.20 watt |
| Answer» A. 493.875 watt | |
| 39. |
A thrust bearing having collars of external and internal diameter as 40 cm and 20 cm respectively, carries an axial load of 3000 N. The co-efficient of friction is 0.09 and shaft runs at 420 rpm. The power lost in friction is to be determined. The corresponding value of friction torque would be ____. |
| A. | 40.5 n-m |
| B. | 42 n-m |
| C. | 45.0 n-m |
| D. | 48.5 n-m |
| Answer» B. 42 n-m | |
| 40. |
A thrust bearing having collars of external and internal diameter as 40 cm and 20 cm respectively, carries an axial load of 3000 N. The co-efficient of friction is 0.09 and shaft runs at 420 rpm. The power lost in friction would be equal to ____. |
| A. | 1.94 kw |
| B. | 1.84 kw |
| C. | 2 kw |
| D. | 2.5 kw |
| Answer» B. 1.84 kw | |
| 41. |
A flat footstep bearing 10 cm radius supports a load of 3 kN. The shaft runs at 600/π r.p.m. and co-efficient of friction is 0.1.The friction torque and frictional power in watts with uniform pressure are respectively. |
| A. | 10 n-m and 400 watts |
| B. | 20 n-m and 400 watts |
| C. | 30 n-m and 600 watts |
| D. | not possible to find for insufficient data |
| Answer» B. 20 n-m and 400 watts | |
| 42. |
A flat footstep bearing 10 cm radius supports a load of 3 kN. The shaft runs at 600/π r.p.m. and co-efficient of friction is 0.1. The friction torque and frictional power in watts with uniform wear are respectively. |
| A. | 30 n-m and 600 watt |
| B. | 15 n-m and 300 watts |
| C. | 15 n-m and 600 watts |
| D. | not possible to find for insufficient data |
| Answer» B. 15 n-m and 300 watts | |
| 43. |
A flat foot step bearing 225 mm in diameter supports a load of 7500 N. If the co-efficient of friction is 0.09 and the shaft rotates at 60 rpm, calculate the power lost in frictional torque and frictional power in watts with uniform pressure is ___. |
| A. | 50.62 n-m and 317.92 watt |
| B. | 60.62 n-m and 320.92 watt |
| C. | 57.68 n-m and 321.92 watt |
| D. | 55.50 n-m and 410.12 watt |
| Answer» A. 50.62 n-m and 317.92 watt | |
| 44. |
Following are the details pertaining to thrust bearing 1) External and internal dia of contacting surfaces-320 mm and 200 mm resp. 2) Axial load-80 kN 3)Pr. Intensity-350 kN/m2 4) shaft speed-400 rpm 5)coefficient of friction-0.06 Calculate power lost in overcoming friction. the frictional torque and power lost in frictional |
| A. | 600.35 nm and 26.60 kw |
| B. | 630.30 nm and 28.40 kw |
| C. | 635.08 nm and 26.60 kw |
| D. | 650.52 nm and 27.35 kw |
| Answer» C. 635.08 nm and 26.60 kw | |
| 45. |
A conical pivot supports a load of 20 kN, and its semicone angle is 41.81 degree. The friction coefficient is 0.06 and shaft runs at 200 rpm. The torque required to overcome friction and power lost in friction is |
| A. | 135.20 nm and 2.93 kw |
| B. | 125.40 nm and 2.93 kw |
| C. | 130.35 nm and 2.53 kw |
| D. | 135.36 nm and 2.83 kw |
| Answer» D. 135.36 nm and 2.83 kw | |
| 46. |
The clutch is a device used______ |
| A. | to absorb frictional torque |
| B. | to absorb frictional power |
| C. | to transmit power from on shaft to another |
| D. | all of the above |
| Answer» C. to transmit power from on shaft to another | |
| 47. |
Advantages of positive clutch is_____ |
| A. | they can be engaged at high speed |
| B. | they cause for high speed application |
| C. | shock and noise is there during engagement |
| D. | due to no slip between contact surfaces no heat is generated |
| Answer» D. due to no slip between contact surfaces no heat is generated | |
| 48. |
Disadvantages of positive clutch is______ |
| A. | they can be engaged at high speed |
| B. | they don’t provide positive engaged |
| C. | shock and noise is there during engagement |
| D. | due to no slip between contact surfaces no heat is generated |
| Answer» C. shock and noise is there during engagement | |
| 49. |
Torque transmitted by friction clutch_______ |
| A. | is more on the assumption of uniform pressure as compared to uniform wear |
| B. | is less on the assumption of uniform pressure as compared to uniform wear |
| C. | is same on the assumption of uniform pressure and uniform wear |
| D. | is more or less on the assumption of uniform pressure as compared to uniform wear depending upon material |
| Answer» A. is more on the assumption of uniform pressure as compared to uniform wear | |
| 50. |
For multiple plate clutch having 'n' is the effective number of surfaces for transmitting power then no. of plates are |
| A. | n+1 |
| B. | n-1 |
| C. | n |
| D. | n-2 |
| Answer» A. n+1 | |
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