GUJARAT TECHNOLOGICAL UNIVERSITY
SEMESTER-IV(NEW) — EXAMINATION - SUMMER 2019
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Subject Code:2142001 Date:17/05/2019
Subject Name: Kinematics & Dynamics of Machines
Time:02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
- Attempt all questions.
- Make suitable assumptions wherever necessary.
- Figures to the right indicate full marks.
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Q.1 (a) State and explain types of constrained motion with figure. 03
(b) Derive an equation for gyro-couple with usual notation 04
(c) What is Coriolis acceleration component? In which cases does it occur? 07 How is it determined?
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Q.2 (a) Define instantaneous center and instantaneous axis. 03
(b) Enlist the types of inversion for (i) four bar kinematic chain (ii) single slider 04 kinematic chain and (iii) double slides kinematic chain.
(c) Fig.1 Shows the toggle mechanism in which the crank OA rotates at a 07 uniform speed of 105 rpm in clock wise direction. Determine the velocity and acceleration of slider P. The lengths of various links are: OA=8 cm, AB=18 cm, BC=24cm and BP=28 cm.
OR
(c) Describe Klein’s construction with an example 07
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Q.3 (a) Derive an equation for length of path of contact for gear train 03
(b) Explain the effects of Gyroscopic couple on an Aero plane with sketch. 04
(c) Explain with a neat sketch the “Sun and Planet wheel”. Write its merits 07 and demerits as compared to reverted and compound gear trains.
OR
Q.3 (a) What are the different types of motion with-which a follower can move? 03
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(b) Derive the condition for correct steering. Sketch and show the Davis 04 steering mechanism and discuss their advantages.
(c) A Flat faced mushroom follower is operated by a cam of minimum radius 07 50 mm and gives a lift of 30 mm. The rise takes place in 120° of cam rotation with SHM followed by a dwell for the next 30° of cam rotation. It returns with equal uniform acceleration and retardation during 90° of cam rotation. The line of action of the follower passes through the axis of the cam. Draw a cam profile and determine the maximum velocity and acceleration of the follower during the outward and return strokes, if the cam rotates at 240 rpm. What should be the minimum width of the follower?
Q.4 (a) Explain the phenomena of ‘slip” and ‘creep’ in a belt drive. 03
(b) Derive the condition for transmitting the maximum power in a flat belt drive. 04
(c) Explain the method of balancing of different masses revolving in same 07 plane
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OR
Q.4 (a) What do you mean by balancing? Why it is necessary for high speed 03 engines?
(b) Explain primary unbalanced force in reciprocating engine. Why 04 reciprocating masses are partially balanced?
(c) What is the smallest number of teeth theoretically required in order to avoid 07 interference on a pinion having pressure angle 22° and module 1 Which is to gear with
- Rack
- A wheel to give a ratio of 3:1.
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Q.5 (a) What is a damped vibration? What are the different types of damping 03 methods?
(b) Distinguish between longitudinal, transverse and torsional vibration. 04
(c) A flat belt runs on a pulley 1 m in diameter and transmits 8kW at 200 rpm. 07 Assuming angle of lap as 170° and coefficient of friction as 0.25. Find the necessary width of belt if the pull is not exceed 200 N/cm width of the belt. Neglect centrifugal tension.
OR
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Q.5 (a) What is meant by vibration isolation and transmissibility? 03
(b) Explain following term. 04
- Time period
- Frequency
- Amplitude and
- Damping.
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(c) What do you understand by degree of freedom? What are the various causes 07 of vibrations? How the effects of undesirable vibrations can be reduced?
Q.2 (c) Fig. 1
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