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DIPLOMA ENGINEERING – SEMESTER – IV-EXAMINATION – WINTER 2015
Subject Code: 3341903 Date: 04/12/2015
Subject Name: Theory of Machine
Time: 02:30 PM TO 5:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make Suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Use of programmable & Communication aids are strictly prohibited.
5. Use of only simple calculator is permitted in Mathematics.
6. English version is authentic.
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Q.1 Answer any seven out of ten.14
1. Define the following terms.(1) Link (2) Lower pair (3) Higher pair(4) Mechanism
2. Differentiate between kinetics and kinematics.
3. Give the four equation of angular motion.
4. Sketch an Oldham’s Coupling.
5. Draw a displacement Diagram for SHM Knife edge follower.
6. Define Base circle and Pitch curve with appropriate figure.
7. State the laws of friction.
8. Explain the working of hydrodynamic lubrication.
9. Define slip in belt drive and explain the effect of slip.
10. Explained damped vibration.
Q.2 (a) State the type of quick return motion mechanisms and explain any one with neat sketch. 03
OR
(a) Sketch and explain any two inversions of a four bar chain. 03
(b) Differentiate structure and machine with suitable example. 03
OR
(b) Classify kinematic pair and explain any one with neat sketch. 03
(c) With a neat sketch explain four bar chain mechanism and draw the velocity and acceleration diagram for the same based on relative velocity method. 04
OR
(c) For a four bar mechanism ABCD, AD = 3.5 m is a fixed link. Driving link AB = 0.5 m, driven link CD = 1.5 m, link BC = 3 m and Angle BAD = 600.Link AB rotates at 20 rpm in clock wise direction, Determine (i) Angular velocity of link BC.(ii)Linear velocity of point E lying on link BC at 2.25 m from B. 04
(d) With neat sketch explain the Klien’s construction to find out the velocity of various links of slider crank chain. 04
OR
(d) In a steam engine, the crank and connecting rod are 300mm and 1500 mm long respectively. Draw the velocity diagram when crank has rotated in clockwise direction for 500from I.D.C. Find the engine speed when the velocity of piston is 4.9 m/s. 04
Q.3 (a) State the various types of thrust bearing and their applications. 03
OR
(a) Derive the expression for the friction torque for a flat pivot bearing assuming uniform pressure. 03
(b) Explain the construction & working of a single plate clutch with neat sketch. 03
OR
(b) A cone clutch transmits 300 N.m torque and has mean cone diameter of 300 mm and semi cone angle of 160.Assuming uniform wear find the axial load and length of the contact surface. Coefficient of friction is 0.3 and permissible pressure of 0.15 N/mm2. 03
(c) Derive the expression for ratio of tension in the tight side to the tension in the slack side for the flat belt drive. 04
OR
(c) A belt having 1 gm/cm3density has maximum permissible stress of 2.2N/mm2. The width & thickness of the belt is 250 mm & 11 mm respectively. If the ratio of the belt tension is 2, find the maximum power that can be transmitted by the belt. 04
(d) List the type of gear train used in gear drive. Derive the expression for train value for a compound gear train. 04
OR
(d) Explain the automobile gear box with sliding gears with a neat sketch. 04
Q.4 (a) Explain Coefficient of fluctuation of energy and Coefficient of fluctuation of speed. 03
OR
(a) Draw the turning moment diagram for four stroke I.C. engine. 03
(b) State the different types of governor and explain working of a centrifugal governor. 04
OR
(b) Define the following terms also give their S.I. unit.(1) Time Period (2) Frequency (3) Cycle (4) Amplitude 04
(c) Draw the cam profile for a disc cam and knife edge follower from the following data for one revolution of cam. Angle of rise = 600, Follower lift = 40 mm with uniform velocity. Angle of dwell (at rise) = 300where the follower moves with uniform velocity. For remaining period of 2100, the follower remains in same position. Diameter of base circle = 50 mm. 07
Q.5 (a) The turning moment diagram for a petrol engine is drawn to the following scale. Turning moment scale, 1cm =5586 N.m, Crank angle scale, 1cm = 300The turning moment diagram repeats itself at every half revolution of the engine crank shaft and the areas above and below the mean torque line taken in order are 2.95, 6.85, 0.4, 3.4, 9.6 and 2.7 sq.cm. The rotating parts are equivalent to 40 kg at a radius of 1.8 m. Determine the coefficient of fluctuation of speed when the engine runs at 1500 rpm. 04
(b) Explain (1) Free vibrations (2) Resonance (3)Forced vibrations (4)Damped vibration. 04
(c) Explain the balancing of several masses rotating in the same plane by analytical method. 03
(d) Three masses 5 Kg, 6Kg and 8Kg are revolving about an axis in the same plane at the radii of 0.12m, 0.1m,0.15m respectively. The angle between 5 Kg and 6 Kg mass is 600and 6 kg and 8 Kg mass is 1650. Determine magnitude and position of the balancing mass at the radius of 0.14 m for the state of balance. 03
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