MCQOPTIONS
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MCQOPTIONS
This section includes 9 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Ball bearings are generally made of- |
| A. | Cast iron |
| B. | Malleable cast iron |
| C. | Carbon steel |
| D. | Chrome steel |
| Answer» E. | |
| 2. |
A journal bearing sustains a radial load of 3672 N. The diameter of the bearing is 50 mm and the length is 0.1 m. The diameter clearance is 0.1 mm and the shaft rotates at 500 r.p.m. if the absolute viscosity of the oil is 0.06 kg/m-s, the value of Sommerfeld number is |
| A. | 5.2 × 106 |
| B. | 10.3 × 106 |
| C. | 15.2 × 106 |
| D. | 20.3 × 106 |
| Answer» C. 15.2 × 106 | |
| 3. |
A journal bearing has shaft diameter of 40 mm and a length of 40 mm. The shaft is rotating at 20 rad/s and the viscosity of the lubricant is 20 mPa.s. The clearance is 0.020 mm. The loss of torque due to the viscosity of the lubricant is approximately |
| A. | 0.040 Nm |
| B. | 0.252 Nm |
| C. | 0.400 Nm |
| D. | 0.652 Nm |
| Answer» B. 0.252 Nm | |
| 4. |
In a single plate clutch μ, F, ro and ri are coefficient of friction, axial force, outer radius and inner radius respectively. The frictional torque using uniform wear theory is equal to |
| A. | \(\frac{1}{2}\mu F ~(r_o+r_i)\) |
| B. | \(\frac{2}{3}\mu F~(r_o+r_i)\) |
| C. | μF (ro +ri) |
| D. | 2μF (ro +ri) |
| Answer» B. \(\frac{2}{3}\mu F~(r_o+r_i)\) | |
| 5. |
Clearance ratio should be increased for bearings of diameter less than |
| A. | 0.1 m |
| B. | 0.01 m |
| C. | 1 m |
| D. | 10 m |
| Answer» B. 0.01 m | |
| 6. |
Bearing characteristics number in a hydrodynamic bearing depends upon |
| A. | viscosity, speed and bearing pressure |
| B. | viscosity, speed and load |
| C. | load, speed and length |
| D. | length, width and speed |
| Answer» B. viscosity, speed and load | |
| 7. |
Consider that modern machines mostly use short bearings due the following reasons:1) l/d of the most modern bearings is in the range of 1.4 to 22) No end leakage of oil from the bearing3) Shaft deflection and misalignment do not affect the operation4) Can be applied to both hydro-dynamic and hydrostatic casesWhich of the above are correct? |
| A. | 1 and 4 |
| B. | 3 and 3 |
| C. | 1 and 3 |
| D. | 2 and 4 |
| Answer» D. 2 and 4 | |
| 8. |
A lightly loaded full journal bearing has a journal of 50 mm, bush bore of 50.05 mm and bush length of 20 mm. if rotational speed of journal is 1200 rpm and average viscosity of liquid lubricant is 0.03 Pa s, the power loss (in W) will be |
| A. | 37 |
| B. | 74 |
| C. | 118 |
| D. | 237 |
| Answer» B. 74 | |
| 9. |
A thick lubrication is |
| A. | A stable lubrication and there is no metal to metal contact |
| B. | A stable lubrication because there is some amount of metal to metal contact |
| C. | An unstable lubrication because there is some amount of metal to metal contact |
| D. | An unstable lubrication because there is no metal to metal contact |
| Answer» B. A stable lubrication because there is some amount of metal to metal contact | |