 # MCQ for Unit 1 BY PROF R S

• Slides: 65 MCQ for Unit 1 BY, PROF. R. S. CHAUDHARI. ASST. PROFESSOR MECHANICAL ENGINEERING DEPARTMENT Question 1 The uniform wear conditions are used ……. . a) for maximum power to be transmitted b) for safe design of clutches c) for safe design of bearings d) for overcoming the frictional torque. Question 2 The uniform pressure conditions are used ……. a) for maximum power to be transmitted b) for safe design of clutches c) for safe design of bearings d) for overcoming the frictional torque. Question 3 For safe design of bearing, we assume ……. . a) maximum power to be transmitted b) safe design of clutches c) safe design of bearings d) overcoming the frictional torque. Question 4 For safe design of clutches, we assume ……. . � a) uniform pressure conditions � b) uniform wear conditions � c) Neither uniform pressure nor uniform wear � d) All of the above. Question 5 According to uniform wear theory ……. � a) P·ω = constant b) P· r = constant � c) P·W = constant d) P·T = constant Question 6 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) ½ r c) 3/2 r d) 2/3 r Question 7 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) = ½ Question 8 Torque required to overcome the friction between shaft and bearing surface in case of multiple flat collar bearing is ……. . �a)Independent of no of collars �b)dependent on radius of collar �C)dependent of no of collars �D)Non of above. Question 9 According to uniform wear theory frictional torque transmitted by conical pivot bearing is …… � a) 2/3 μ W R cosec α � b) 1/2 μ W R cosec α � c) 1/2 μ W R cos α � d) μ W R cosec α Question 10 Frictional torque as per uniform wear theory is …………. � (a)µP(R 0+Ri) (b)½ µP(R 0+Ri) � (c) ½ µP Question 11 In case of flat pivot bearing, the rubbing velocity is……… � (a)maximum at the centre of the contact area � (b)zero at the centre & maximum at the outer radius � (c)uniform throughout the contact area � (d) zero at the outer radius Question 12 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 proportional to the pressure intensity � (d)both (b) &(c) Question 13 For calculating the friction power of bearing, the assumptions made in practise 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) & (c) only Question 14 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 Question 15 The frictional torque, transmitted in case of flat pivot bearing for uniform pressure, is equal to……… � (a)µWR (b) µWR � (c) µWR (d) µWR Question 16 In case of flat pivot bearing, the frictional torque transmitted for uniform pressure as compared to the frictional torque transmitted for uniform wear Is equal to…. . � (a)µWR (b) µWR � (c) µWR (d) µWR Question 17 The ratio of frictional torque for uniform pressure to the frictional torque transmitted for uniform wear in case of flat pivot, is equal to……. � (a) 1/3 (b) � (c)1. 0 (d) Question 18 The frictional torque, transmitted in case of a flat collar bearing for uniform pressure , is equal to……… � (a)µW (b) � (c)(R 1+R 2) (d)(R 1 -R 2) Question 19 The frictional torque for the same diameter in a conical bearing is _____ than in a flat bearing. (a) more (b) less � (c)equal �(d)may be more or less Question 20 The frictional torque transmitted by a conical collar bearing is _______. � (a)less than that of flat collar bearing (b)equal than that of flat collar bearing � (c)more than that of flat collar bearing �(d)none of the above Question 21 The frictional torque produced due to friction for same shaft diameter, in conical bearing is ___. �(a)less than that for flat bearing �(b)equal to that for flat bearing �(c)more than that for flat bearing �(d) may be more or less depending upon cone angle Question 22 Choose the wrong statement. � (a)The frictional torque transmitted by a shaft fitted with a large number of collers is the same as transmitted by a shaft with one coller. � (b)The frictional force for uniform pressure , in case of a flat pivot bearing, can be assumed to be acting at distance of 2/3 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 pressured, in case of a flat coller bearing, can be assumed to be acting at distance of 1/2 of the sum of internal and external radii of the shaft. Question 23 The frictional torque transmitted in a conical pivot bearing , concider uniform wear , is ____. � (a)1/2 × µ×W×R ×cosecα (b) 3/2 × µ×W×R ×cosecα � (c) 3/4 × µ×W×R ×cosecα (d) µ×W×R ×cosecα Question 24 For pivot bearing with r₁ & r₂ as the outer and inner radii & W as the axial load, the frictional torque , assuming uniform pressure is given by ______. � (a) 1/2× µ×W (r₁ + r₂) (b) 1/2× µ×W (r₁ - r₂) � (c) 2/3 ×µ×w( (r 13 -r 23)/(r 12 –r 22)) (d) ) 2/3 × Question 25 For coller bearing with r₂ & r₁ as inner and outer radii & W as axial load, assuming uniform wear, is given by ______. � (a) 1/2× µ×W (r₁ + r₂) (b) 1/2× µ×W (r₁ - r₂) � (c) 2/3 ×µ×w( (r 13 -r 23)/(r 12 –r 22)) (d) ) 2/3 ×µ×w( (r 13 -r 23)/(r 12 +r 22)) Question 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 Question 27 In case of pivot bearing the rate of wear is ______. � (a)maxm at the center of contact area � (b) zero at the center of contact area � (c)uniform throughout the contact area (d) zero at the maximum radius of the contact area Question 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 increase intensity of pressure Question 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 connot be predicted Question 30 In flat pivot bearing the total power lost in friction ______ � 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 same as that for uniform pressure � d) for uniform wear may be more or less pressure and connot be predicted Question 31 The frictional torque produced in case of flat pivot bearing for uniform wear and uniform pressure respectively is (W = total axial load, µ =co-efficient of friction, r =radius of pivot) �a)1/2µ W r and 2/3 Wµ r �b)2/3µ W r and 1/2µ W r �c)1/3µ W r and 1/2µ W r �d)1/2µ W r and 1/3µ W r Question 32 To be on the safe side in design , the uniform 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 Question 33 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 �assumed Question 34 choose the correct statement for safe design �a) for power transmitted by friction uniform wear is assumed � b) for powertransmitted friction uniform pressure is assumed � c) for power lost in friction and power transmitted uniform wear is assumed � d) for power lost in friction and power transmitted uniform pressure is �assumed Question 35 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 pressures on the �bearing � d) Increase th e power absorbed by the bearing Question 36 Frictional torque produced for uniform pressure for conical pivot � Bearing having semi angle of cone = α is equal to_____ �A)µ W r 1/2 �B)2 µ W r 1/3 �C)µ W r 1/3 �D)3 µ W r 1/4 Question 37 Frictional torque developed due to uniform wear for conical Bearing with semi cone angle = α is_____ �A)µ W r 1/2 �B)2 µ W r 1/3 �C)µ W r 1/3 �D)3 µ W r 1/4 Question 38 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 Question 39 Brakes are self-energizing when …………. . �A)Frictional torque assists the applied torque. �B)Frictional torque opposes the applied torque. �C)Frictional torque vanishes. �D)None of above. � Question 40 In a differential band brake, as shown in fig. 1 the length OA is greater than OB. In order to apply the brake, the force at C should …………. . �A)Be zero. �B)Act in downward direction �C)Act in upward direction �D)None of the above Question 41 For the brake to be self locking, the force P at C as shown in figure 1 should……. . �A)Be zero �B)Act in downward direction �C)Act in upward direction Question 42 When brakes are applied to all four wheels of a moving car, the distance travelled by the car before it is brought to rest, will be……. . �A)Maximum b) minimum �C)Both a and b d) none of the above Question 43 Which of the following brakes is commonly used in two wheelers? �A)Disc brake �B)Band brake �C)Internal expanding shoe brake �D)A and B Question 44 Brakes commonly used in trains are ……… brakes �A)Band �B)Shoe �C)Band block �D)Internal expanding shoe Question 45 In a self locking brake, the force required to apply the brake is……… �A)Minimum �B)Maximum �C)Zero �D)None of the above Question 46 When the frictional force helps the applied force in applying the brake, the brake is ……… �A)Self locking �B)Automatic �C)Self-energising �D)A and C Question 47 In an internal expanding shoe brake, more than 50% of the total braking torque is supplied by…. . �A)Leading shoe �B)Trailing shoe �C)Any of the two �D)None of these Question 48 which of the following is classified a absorption type of dynamometer ? � a) prony brake dynamometer � b) rope brake dynamometer � c) hydraulic dynamometer � d) all of above Question 49 which of the following is classified as transmission type of dynamometer � a) prony brake dynamometer � b) rope brake dynamometer � c) hydraulic dynamometer � d) epicyclic dynamometer Question 50 which of the following is an absorption type of dynamometer ? �a) prony brake dynamometer � b) rope brake dynamometer � c) epicyclic-train dynamometer � d) both (a) & (b) Question 51 in transmission type of dynamometers , the available power is …………. �a) absorbed in overcoming the frictional work. � b) transmitted except that the small power is absorbed due to friction. �c) fully transmitted. �d) none of the above Question 52 an example of absorption type dynamometer is…………. . �a) prony brake dynamometer �b) epicyclic-train dynamometer �c) torsion dynamometer �d) belt transmission dynamometer Question 53 an example of transmission type dynamometer is…………. . �a)prony brake dynamometer �b)rope brake dynamometer �c) Froude dynamometer �d) torsion dynamometer Question 54 which of the following is classified as absorption dynamometer ? � a) prony brake dynamometer � b) rope brake dynamometer � c) Froude ’shydraulic dynamometer �d) all of the above Question 55 � which of the following is classified as transmission dynamometer? � a) torsion dynamometer � b) Froude ’s hydraulic dynamometer � c) belt dynamometer or tathamdyanamometer � d) prony brake dynamometer Question 56 cooling water is use in……………. � a)prony brake dynamometer � b)epicyclic gear train dynamometer � c)torsion dynamometer �d)rope brake dynamometer Question 57 tatham dynamometer is name given to ……………… �d)rope brake dynamometer �b) belt transmission dynamometer �c) absorption dynamometer �d) epicyclic train dynamometer Question 58 incase of glibson flash light torsion dynamometer angle of twist can be measured upto………………. . �a) 1 th /20 and degree �b) 1 th /10 of degree �c) 1 th /70 of degree �d) 1 th /100 of degree Question 59 in case of dynamometer function of counter weight is to �a)balance the brake when unloaded �b)adjust pressure on pulley to control speed. �c)prevent rotation of block due to friction between block and pulley �d) to clamp the block Question 60 F the force at lever end acts as downwards then condition for self-locking is � (a) b/a<e^u for counter-clockwise direction � (b) b/a<e^u fo clockwise direction � (c) b/a<e^u for both direction � (d) none of above Thanks   Unit 3 Answers Que. Ans No 1 B 11 B 21 C 31 A 41 A 51 B 2 C 12 D 22 D 32 B 42 C 52 A 3 A 13 D 23 A 33 B 43 D 53 D 4 B 14 A 24 C 34 A 44 B 54 D 5 B 15 B 25 A 35 C 45 C 55 C 6 B 16 D 26 D 36 D 46 C 56 D 7 A 17 D 27 B 37 A 47 A 57 B 8 A 18 B 28 C 38 B 48 D 58 D 9 B 19 A 29 B 39 B 49 D 59 A 10 B 20 C 30 B 40 B 50 D 60 B