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This set of Theory of Mechanics Multiple Choice Questions & Answers (MCQs) focuses on Theory Of Mechanics Set 2
Q1 | The ratio of frictional torque produced for uniform wear to that for uniform pressure is ____.
- 1
- (2/3)
- (4/3)
- (3/4)
Q2 | In case of pivot bearing the rate of wear is _____.
- maximum at the center of the contact area
- zero at the center of contact
- uniform throughout the contact area
- zero at the maximum radius of the contact area
Q3 | The number of collars are provided to carry a fixed axial force in a flat collar bearing _______.
- to increase torque
- to decrease torque
- to decrease intensity of pressure
- to decrease intensity of pressure
Q4 | In flat pivot bearing the total moment of friction force______.
- for uniform wear is greater than that for uniform pressure
- for uniform wear is less than that for uniform pressure
- for uniform wear is equal to that for uniform pressure
- for uniform wear may be more or less and cannot be predicted
Q5 | To be safe side in the design, the unform pressure and uniform wear is assumed respectively_____.
- for power transmitted by friction and power lost due to friction
- for power lost due to friction and power transmitted by friction
- for torque transmitted by friction and friction torque overcome
- none of the above
Q6 | Choose the correct statement for safe design.
- for power lost in friction uniform wear is assumed
- for power lost in friction uniform pressure is assumed
- for power transmitted due to friction uniform pressure is assumed
- for power transmitted due to friction or lost in friction uniform wear is assuned
Q7 | Choose the correct statement for safe design.
- for power transmitted by friction uniform wear is assumed
- for power transmitted by friction uniform pressure is assumed
- for power lost in friction and power transmitted uniform wear is assumed
- power lost in friction and power transmitted uniform pressure is assuned
Q8 | The purpose of providing multiple collars on a flat collar pivot bearing is to ____.
- establish self sustaining bearing conditions
- increase the frictional resistance
- distribute the axial load because of limiting bearing pressure on bearing
- increase the power absorbed by the bearing
Q9 | In a multi-collared thrust bearing consisting of 'n' collars and subjected to axial load W, load sheared by each collar is _______.
- w
- w/n
- w/(n-1)
- none of these
Q10 | 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 ___.
- 11.25 n-m
- 15 n-m
- 18.50 n-m
- 20.0 n-m
Q11 | 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 ___.
- 11.25 n-m
- 15 n-m
- 18.50 n-m
- 20.0 n-m
Q12 | 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 ___.
- 650 watt
- 880 watt
- 659.7 watt
- 680.20 watt
Q13 | 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 ___.
- 493.875 watt
- 880 watt
- 659.7 watt
- 680.20 watt
Q14 | 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 ____.
- 40.5 n-m
- 42 n-m
- 45.0 n-m
- 48.5 n-m
Q15 | 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 ____.
- 1.94 kw
- 1.84 kw
- 2 kw
- 2.5 kw
Q16 | 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.
- 10 n-m and 400 watts
- 20 n-m and 400 watts
- 30 n-m and 600 watts
- not possible to find for insufficient data
Q17 | 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.
- 30 n-m and 600 watt
- 15 n-m and 300 watts
- 15 n-m and 600 watts
- not possible to find for insufficient data
Q18 | 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 ___.
- 50.62 n-m and 317.92 watt
- 60.62 n-m and 320.92 watt
- 57.68 n-m and 321.92 watt
- 55.50 n-m and 410.12 watt
Q19 | 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
- 600.35 nm and 26.60 kw
- 630.30 nm and 28.40 kw
- 635.08 nm and 26.60 kw
- 650.52 nm and 27.35 kw
Q20 | 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
- 135.20 nm and 2.93 kw
- 125.40 nm and 2.93 kw
- 130.35 nm and 2.53 kw
- 135.36 nm and 2.83 kw
Q21 | The clutch is a device used______
- to absorb frictional torque
- to absorb frictional power
- to transmit power from on shaft to another
- all of the above
Q22 | Advantages of positive clutch is_____
- they can be engaged at high speed
- they cause for high speed application
- shock and noise is there during engagement
- due to no slip between contact surfaces no heat is generated
Q23 | Disadvantages of positive clutch is______
- they can be engaged at high speed
- they don’t provide positive engaged
- shock and noise is there during engagement
- due to no slip between contact surfaces no heat is generated
Q24 | Torque transmitted by friction clutch_______
- is more on the assumption of uniform pressure as compared to uniform wear
- is less on the assumption of uniform pressure as compared to uniform wear
- is same on the assumption of uniform pressure and uniform wear
- is more or less on the assumption of uniform pressure as compared to uniform wear depending upon material
Q25 | For multiple plate clutch having 'n' is the effective number of surfaces for transmitting power then no. of plates are
- n+1
- n-1
- n
- n-2