Dynamics Of Machinery B.Tech Question Paper : vardhaman.org
College : Vardhaman College Of Engineering
Degree : B.Tech
Department : Mechanical Engineering
Semester : V
Subject : Dynamics Of Machinery
Document type : Question Paper
Website : vardhaman.org
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Dynamics Of Machinery Question Paper :
Four Year B. Tech V Semester Supplementary Examinations June – 2014
(Regulations [/u][/b]: VCE-R11)
(Mechanical Engineering)
Date : 12 June, 2014 FN
Time: 3 hours
Max Marks: 75
Answer ONE question from each Unit
All Questions Carry Equal Marks
Related : Vardhaman College Of Engineering Power System Transmission & Distribution B.Tech Question Paper : www.pdfquestion.in/6365.html
All parts of the question must be answered in one place only :
Unit – I :
1. a) Obtain an expression for gyroscopic couple? 5M
b) An aero plane makes a complete half circle of 50 m radius towards left when flying at 200 Km/hr. The mass of the rotary engine and propeller is 400 kg with a radius of gyration 300 mm. The engine runs at 3000 rpm counterclockwise when viewed from the rear. Determine the gyroscopic couple and its effect on the aircraft. 10M
2. a) What is lubrication? Explain the differences between thin film lubrication, boundary lubrication & fluid film lubrication? 7M
b) An effort of 1500 N is required to just move a certain body up an inclined plane of angle 120, force acting parallel to the plane. If the angle of inclination is increased to 150, then the effort required is 1720 N. Find the weight of the body and the coefficient of friction. 8M
Unit – II :
3. a) With a neat sketch, explain the working of a multi plate friction clutch? 7M
b) A cone clutch with a semi cone angle of 150 transmits 10 KW at 600 rpm. The normal pressure intensity between the surfaces in contact is not to exceed 100 Kpa. The width of the friction surface is half of the mean diameter. Assume ? =0.25 and determine:
i. The outer & inner diameters of the plates
ii. Width of cone face
iii. The axial force necessary to engage the clutch 8M
4. a) A simple band brake of drum diameter 600 mm has a band passing over it with an angle of contact of 2700, while one end is connected to the fixed pin, the other end is connected to the brake lever at a distance of 125 mm from the fixed pin. The brake lever is 750 mm long. The brake is to absorb a power of 35 KW at 200 rpm. Coefficient of friction f=0.25.Determine:
i. The minimum pull necessary & the direction of rotation.
ii. Width of 3 mm thick steel band if the tensile stress is not to exceed 55 N/mm2 8M
b) Differentiate between absorption type & transmission type dynamometers. Explain any one type of absorption dynamometer with a neat sketch. 7M
Unit – III :
5. a) Explain the applications of governors. 5M
b) Draw a neat sketch of a Proell Governor and explain the working. 10M
6. The mass of each ball of a Proell governor is 7.5 kg and the load on the sleeve is 80kg. Each of the arms is 300mm long. The upper arms are pivoted on the axis of rotation whereas the lower arms are pivoted to links of 40mm from the axis of rotation. The extensions of the lower arms to which the balls are attached are 100mm long and parallel to the governor axis at the minimum radius. Determine the equilibrium speeds corresponding to the extreme radii of 180mm and 240mm. 15M
Unit – IV :
7. a) Explain the necessity for balancing of rotating masses? 5M
b) A rotating shaft carries four masses 1, 2, 3 & 4 which are radially attached to it. The mass centers are 30 mm, 38 mm, 40 mm and 35 mm respectively from the axis ofrotation. The masses 1, 3 and 4 are 7.5, 5, & 4 kg respectively. The axial distance between the planes 1 and 2 is 400 mm & between 2 and 3 is 500 mm. The masses 1 & 3 are at right angles to each other. Find for complete balance:
i. Angle between 1, 2 & 1, 4
ii. Axial distance between 3 & 4
iii. Magnitude of mass 2 10M
8. Four masses A, B, C and D are completely balanced. Masses C and D make angles 900 and 1950 respectively with B in the same sense. The rotating masses have the flowing properties Mb = 25kg, mc = 40kg, md = 35kg, ra = 150mm, rb = 200mm, rc= 100mm, rd = 180mm. Planes B and C are 250mm apart. Determine Mass A and its angular position. 15M
Unit – V :
9. a) Explain with neat sketch damped vibrations? 6M
b) Derive an equation for Dunkerleys method? 9M
10. a) Write short notes on whirling of shafts. 7M
b) A cantilever shaft 50 mm diameter and 300 mm long has a disc of mass 100 kg at its free end. The Young’s modulus for the shaft material is 200 GN/m2. Determine the frequency of longitudinal and transverse vibrations of the shaft. 8M