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GUJARAT TECHNOLOGICAL UNIVERSITY
DIPLOMA ENGINEERING – SEMESTER – IV • EXAMINATION – SUMMER- 2016
Subject Code: 3341903 Date: 17-05-2016
Subject Name: Theory of Machines
Time: 10:30 A.M to 1:00 P.M 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. What is inversion of mechanism?
2. Define the following terms. (1) Link (2) Mechanism.
3. Define the following terms. (1) Lower pair (2) Higher pair.
4. Differentiate between machine and mechanism.
5. What is turning pair? Give example of turning pair.
6. What is friction? List types of friction.
7. What is dynamometer? List types of dynamometer.
8. Define cam and state the function of cam.
9. Differentiate between Flywheel and Governor.
10. Explain (1) Forced vibrations (2) Damped vibration.
Q.2 (a) Draw neat Sketch of any one inversions of a slider crank mechanism. 03
OR
(a) Draw neat Sketch of any one inversions of a Double-slider crank mechanism. 03
(b) Differentiate between brake & Dynamometer. 03
OR
(b) Explain working of plate clutch with line diagram. 03
(c) With neat sketch explain the Klein’s construction to find out the velocity of various links of slider crank chain. 04
OR
(c) With neat sketch explain relative velocity method to find velocity and acceleration of four bar chain. 04
(d) The crank of a steam engine is 150 mm long and the connecting rod is 600 mm long. The crank is at 30° from IDC and engine speed is 240 rpm clock wise. Find (i) velocity and acceleration of piston. Use relative velocity and acceleration method. 04
OR
(d) Solve above example (Que.2 (d)) using Klein’s construction method. 04
Q.3 (a) Classify mechanical power transmission & state advantages of chain drive. 03
OR
(a) From the following details for the open belt drive, find the necessary width and initial tension in the belt.
(1) Diameter of pulley=600 mm
(2) Arc of contact= 3 rad.
(3) co-efficient of friction=0.4
(4) power transmitted at 400 rpm= 4 KW
(5) Safe tension for belt [T] = 10N/mm width. 03
(b) A leather belt 200 mm ×10 mm is of density 1.1 gm/cc. its maximum permissible tension is 200 N/cm2. If the ratio of tensions is 1.8, determine maximum power transmitted? 03
OR
(b) A conical bearing in the form of frustum of cone has a mean diameter of 200 mm.it supports an axial load of 40 KN. The semi cone angle is 45°, and μ=0.05.determine the power lost in friction at 100 rpm. 03
(c) Derive the expression Tc=mv² with usual notation and assumptions. 04
OR
(c) Prove that Ratio of driving tensions for flat belt drive is 2.3log (T1/T2) = μθ. 04
(d) Explain Compound Gear train. 04
OR
(d) Explain Epicyclic Gear train. 04
Q.4 (a) Derive the expression for the friction torque for a flat pivot bearing assuming uniform pressure. 03
OR
(a) State the various types of thrust bearing and their applications. 03
(b) Explain turning moment diagram for Four stroke cycle IC engine. 04
OR
(b) Explain the term “fluctuation of Energy” and “fluctuation of speed” as applied to the flywheel. 04
(c) A disc cam is used to give motion to a knife edge follower. For the 1st1200of cam revolution, follower moves up 60 mm with simple harmonic motion. For the next 600 of cam revolution, follower remains at rest. For the next 1200 of cam revolution follower comes down with uniform velocity. For remaining period of cam revolution it remains at rest. Diameter of base circle of cam is 50 mm. assume cam rotates in anti-clockwise direction. Draw cam profile. 07
Q.5 (a) What is vibration? State causes of vibration & measures to reduce vibrations. 04
(b) Explain with neat sketch the working of Hartnell Governor. 04
(c) Explain the balancing of several masses revolving in the same plane by analytical method. 03
(d) List types of followers and explain any one with figure. 03
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