(Tom i) Question Bank

8/8/2019 (Tom i) Question Bank

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SREE NARAYANA GURUKULAM COLLEGE OFENGINEERING,KADAYIRUPPU,KOLANCHERY

QUESTION BANK-1

Part A

1. State and prove Kennedy s theorem.

2. Differentiate between a mechanism and a machine.

3. Briefly explain the number synthesis.

4. What are the features of kinematic synthesis

5. With a neat sketch, explain the Scott-Russel mechanism

6. Briefly explain the working of a Pantograph.

7. Write a note on classification of brakes.

8. What is meant by torsion dynamometer? Explain.

9. What is the condition for constant velocity ratio in gears? Explain.

10. Define (i) Arc of contact ;(ii)Path of contact; and (iii)Contact ratio.

(10x4=40)

Part B

11. With the help of neat sketches, explain any three mechanismswhich are the inversion of a single slider crank chain used inengineering practice


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Or

12.The crank and slotted lever has the maximum stroke length of 300mm Maximum velocity ratio is 2.Determine(i)Length of slottedlever;(ii)Ratio of times of cutting and return stroke

Or

13. (a)Explain the overlay method of kinematic synthesis

(b)What are the graphic methods of dimensional synthesis?

14. Explain the procedure to obtain the chebyshev spacing for threeprecision points given y=x .8for the range 1


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friction = .15 and the permissible intensity of pressure is.5N/mm.Calculate the number of steel and bronze disks.

19. What do you understand by Interference as applied to gears?Derive an expression for for minimum number of teeth required on thepinion in order to avoid interference in gear teeth

Or

20. (a) Derive an expression for efficiency of worm gears.

(b)Write a note on standard and non standard gear tooth properties


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QUESTION BANK-2

Part-A

1. Obtain the instantaneous centre of a four-bar chain and explain howthese can be used for the velocity analysis.

2. Distunguish between (a) Higher pair and Lower pair ;(b)Revolute pair;(c)Mechanism and Machine.

3. Write down the mechanisms used in practice which are theinversions of a (a) single slider crank chain; and (b) double slider crankchain.

4. Explain the overlay method of kinematic synthesis.

5. With a neat sketch, any one type of approximate straight linemechanism.

6. What are the geometrical properties of coupler curves?

7. Explain with a neat sketch the function of an air brake.

8. Differentiate between Absorption and Transmission dynamometers


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9. Obtain an expression for virtual no. of teeth in case of helical gears.

10. Obtain an expression for back lash in spur gear drive fromfundamentals.

(10x4=40 marks)

Part B

11. Write a neat sketch of any one six bar kinematic chain. Explain howis the acceleration of the output link obtained given the velocity andacceleration of the input link, for this mechanism.

Or

12. In a four bar linkage ABCD shown in figure find the angular velocityof BC, Velocity of C, velocity of E on BC and velocity of G on CD by usinginstantaneous centre method. The link AB revolves with angularvelocity radians/sec

13. Draw a neat line diagram of a whit worth quick return mechanism.Explain the procedure step-by-step, in order to determine the velocityof the ram given the angular velocity of the ram given the angularvelocity of the crank using instant centre method.

Or

14. With the help of line diagrams, distinguish between closed pair andunclosed pair. What do you mean by quick return moton? How is itachieved in practice? Write down the proportionate sketches of twotypes of quick return mechanisms in order to answer this question.


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15. Write down a neat line diagram of a slider crank chain used for ICengines. Explain the step-by-step procedure to perform the velocity andacceleration analysis of such mechanism.

Or

16. Write and explain (a) Davis steering gear; and (b) Ackermannsteering gear.

17. A band and block brake having 12 blocks each subtending an angle

of 14 at the centre is applied to a rotating drum having 105cm.diameter the blocks are 5 cm. Thick. The two ends of the band areattached to pins on the opposite sides of the brake lever at distance of 2 cm. and 8cm. from the fulcrum .What is the minimum force requiredto be applied at the end of a lever one meter long for the rake toabsorb 300 hp t 250 r.p.m. between blocks and drum =.35

Or

18. Write and explain different types of dynamometers.

19. (a) List down the major advantages enjoyed by involutes toothprofile over cycloid profile. What are the advantages of involutes toothprofile over cycloidal tooth profile?

(b)Explain the phenomenon of Back lash in standard spur gears.

Or

20(a) what do you mean by interference in case of involute spur gearrives? How it is eliminated in practice?


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(b)A three start worm has a pitch diameter of 80 mm and a pitch of 20mm .it rotates at 600 r.p.m and drives a 40 teeth worm gear. If thecoefficient of friction is .05, find

(i)The helix angle of the worm (ii) Speed of the gear

(iii)Centre distance (iv) Efficiency of the drive.

(v)Maximum efficiency


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QUESTION BANK-3

Part-A

1. What is meant by coriolis compound of acceleration?

2. Mention any two applications of the Quadric cycle chain.


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3. Briefly explain any one method of dimensional synthesis?

4. What are the basic features of Mechanical synthesis?

5. With a neat sketch, explain a Grasshopper mechanism.6. List the indicator mechanisms which work on the straight linemotion. Explain briefly.

7. Explain the conditions of self locking in shoe brakes.

8. What is the principle of working of a torsion dynamometer?

9. What are the advantages of cycloidal gears over involute gears?10. Explain with a neat sketch , the various forces acting on a spurgears.

(10x4=40 marks)

Part B

11. In a four bar chain, ABCD , link AD is fixed and the crank AB rotatesat 10 radians per second clockwise. Length s of the links are AB=60mm,BC=CD=70mm,DA=120mm.When angle DAB=60 and both B and Clie on the same side of AD, find

(i) Angular velocities (magnitude and direction) of BC and CD.

(ii) Angular acceleration of BC and CD.

Or

12. What do you understand by coupler curves? Describe the methodof obtaining the co-ordinates of a coupler point in.

(i)Four bar mechanism


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(b) Centrifugal clutches.

(c)Epicyclic train.

Or

18.A multiple disk clutch , steel on a bronze is to transmit 3.68 kW at750rev/min.The inner radius of contact is 38 mm and the outer radiusof contact is 70 mm.The clutch operates in oil with an expectedcoefficient of friction 0.10.The average pressure is0.35N/mm.Determine (a)total disks of steel and bronzerequired;(b)axial force required

19. (a)What do you understand by the term Interference as applied togears.

(b)Derive an expression for the minimum number of teeth required onthe pinion in order to avoid interference in involute gear teeth.

Or

20. Two gear wheels externally mesh are to give a velocity ratio of 3 to1.The teeth are of involute form, module=6mm addendum =1 module,pressure angle=20 .The pinion rotates at 90 r.p.m.Determine

(a)Number of teeth on the pinion to avoid interference.

(b)Length of path and arc of contact.(c)The number of pairs of teeth in contact.

(d)The maximum velocity of sliding.


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QUESTION BANK-4

Part-A

1. With the help of neat diagram, explain all types of kinematic pairs.

2. State and prove Arnold Kennedy s theorem of three centers.

3. Explain the graphical method of synthesis for a four bar chain withthree precision points.

4. Explain how to synthesise a function generator mechanism.

5. Write the schematic of a crank and slotted lever mechanism.


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6. Where do you find the applications of exact and approximate straightline mechanisms?

7. With a neat sketch explain the working of a mechanical brakesystem.

8. What is meant by rope brake dynamometers? Explain.

9. Obtain an expression for the pressure angle.

10. Explain the significance of contact ratio in gear drives and derive anexpression for the same.

Part B

11(a) With the aid of neat sketches, explain all five types of kinematicpairs.

(b)Derive an expression for the degree of freedom of a planar kinematicchain with lower pairs.

Or

12. With the help of neat sketches, explain any three mechanismswhich are the inversions of a double slider crank chain used inengineering practice.

13. Write a neat line diagram of a Whitworth mechanism. With the helpof diagram, explain how the acceleration of the tool holderdetermined.Given the angular velocity is and angular acceleration of the input link in this mechanism.

Or


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14. What are the advantages of a Single Hooks joint? How they areovercome in practice?

A Hooks joint is to convert two shafts whose axes intersect at 150.The driving shaft rotates uniformly at 120 r.p.m.Determine themaximum and minimum speeds of above driven shaft.

15. Explain how is the kinematic synthesis performed for a four barchain for

(a)Three precision points.(b)Two precision points

Explain two precision synthesis or a single slider crank chain.

Or

16. Design a slider crank mechanism graphically for the following

details:-12=30 ; 23=50 ; 12=30 mm ,e=10mm.

17. (a) Write a short note on overlay method of kinematic synthesis.

(b)Explain what is meant by Type synthesis, Number synthesis,

Dimensional syntesis and rigid body guidance with the aid of suitableexamples.

Or


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18. A simple band brake operates on a drum of 600 mm.in diameterthat is running at 200 r.p.m.The coefficient of friction is .25.The brakeband has a contact of 270 one end is fastened to a fixed pin and the

other end to the brake arm 125mm.from the fixed pin The straightbrake arm is 750 mm.long and placed perpendicular to the diameterthat bisects the angle of contact

(a)What is the pull necessary on the end of the brake arm to stop thewheel is 35kW is being absorbed? What is the direction for thisminimum?

(b)What width of steel band of 2.5 mm .thick is required for this brake if the maximum tensile stress is not to exceed 50N/mm?

19.(a)Derive an expression for the velocity of sliding in case of a spurgear with the help of a neat sketch from fundamentals.

(b)Write a detailed note on standard and non standard gear toothproperties.

Or

20(a) An epicyclic gear consists of a pinion wheel 0f 40 teeth and anannulus with 84 internal teeth concentric with the wheel. The piniongears with wheel and the annulus .The arm that carries the axis of thepinion rotates at 100 r.p.m. If the annulus is fixed, find the speed of thewheel; if the wheel is fixed find the speed of the annulus.

(b)Derive an expression for the efficiency of worm gears.


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