Question Paper: Theory of Machines 1 : Question Paper Jun 2015 - Mechanical Engineering (Semester 4) | Pune University (PU)
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## Theory of Machines 1 - Jun 2015

### Mechanical Engg (Semester 4)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.

### Answer any one question from Q1 and Q2

1 (a) Define 'Inversion'. Explain with the help of neat sketches any two inversions of double slider crank chain.(5 marks) 1 (b) Write a note on 'Dynamically Equivalent System'.(5 marks) 2 (a) Compare 'Davis' and 'Ackermann' Steering Gear Mechanisms.(4 marks) 2 (b) With the help of neat schematic diagram, derive frequency equation of bifilar suspension system.(6 marks)

### Answer any one question from Q3 and Q4

3 (a) Determine the dimensions of the contact surfaces of cone clutch, for the following specifications:
(i) Power transmission capacity = 20 kW
(ii) Speed = 1600 RPM
(iii) Cone angle = 30°
(iv) Maximum intensity of pressure = 0.8 ? 10 5 N/m2.
(v) Coefficient of friction = 0.3
(vi) Mean radius is twice the width of the friction surface.
Assume uniform wear condition.
(5 marks)
3 (b) Explain Complex Algebra method of acceleration analysis for a binary link.(5 marks) 4 (a) Describe with neat sketch the construction and working of epicyclic train type dynamometer.(5 marks) 4 (b) Derive an equation for velocity of piston in an I.C. engine mechanism, when crank rotates with uniform angular velocity using analytical method.(5 marks)

### Answer any one question from Q5 and Q6

5 (a) State and explain Kennedy's theorem.(4 marks) 5 (b) In the mechanism shown in Fig. 1, the crank OA rotates at 20 RPM in anticlockwise direction and gives motion to the sliding blocks B and D. For the given configuration of mechanism, determine by relative velocity method and relative acceleration method:
(i) Velocity of sliders B and D
(ii) Angular velocity of link CD
(iii) Acceleration of sliders B.
OA = 300 mm, AB = 1.2 m, BC = CD = 450 mm
(11 marks)
6 (a) With the help of neat sketch, explain the concept of 'Velocity Image Principle'.(4 marks) 6 (b) In the mechanism shown in Fig. 1 the crank OA rotates at 20 RPM in anticlockwise direction and gives motion to the sliding locks B and D. For the given configuration of mechanism, locate all instantaneous centres of rotation, then determine:
i) Velocity of sliders B and D
ii) Angular velocities of links AB and CD.
(11 marks)

### Answer any one question from Q7 and Q8

7 (a) What is Coriolis acceleration ? Find the direction of this acceleration in the case shown in Fig. 2. (4 marks) 7 (b) The crank of an engine is 180mm long and obliquity ratio is 4. Determine the velocity and acceleration of the piston, when the crank is turned through 40° from I.D.C. position for the following two cases:
(i) The crank rotates at a uniform speed of 300 RPM
(ii) The crank rotates at a speed of 300 RPM and is increasing at the rate of 120 rad/s2.
(11 marks)
8 (a) Explain the procedure to construct Klein's construction to determine the velocity and acceleration of a piston an I.C. engine mechanism, when crank rotates at a uniform angular velocity.(4 marks) 8 (b) The driving crank AB of length 75 mm for the quick return mechanism, as shown in Fig. 3 revolves at a uniform speed of 200 RPM. Find acceleration of point Q, for the configuration shown, when the crank makes an angle of 60° with the vertical line of centres PA. (11 marks)