MORE IN Dynamics of Machines
RGPV Mechanical Engineering (Semester 5)
Dynamics of Machines
December 2015
Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

1(a) Discuss turning moment of crank shaft.
2 M
1(b) Prove that if the external moment is applied to a link, the constraint forces form a couple.
2 M
1(c) State the function of flywheel. State forces acting on it.
3 M
Solve any one question from Q.1(d) & Q.1(e)
1(d) Deduce the expression for the inertia force in the reciprocating force neglecting the weight of the connecting rod.
7 M
1(e) The torque delivered by a two stroke engine is represented by T=(1000+300 sin2θ-500cos2θ)N-m where θ is the angle turned by the crank from the IDC. The engine speed is 250 rpm. The mass of the flywheel is 400kg and radius of gyration 400mm. Determine:
i) The power developed
ii) The total percentage fluctuation of speed.
7 M

2(a) What is the function of governor? What is meant by hunting?
2 M
2(b) Define:
i) Sensitiveness of a governor.
ii) Coefficient of sensitiveness
2 M
2(c) How governors are classified? Explain the effect of Gyroscopic couple on an Aeroplane.
3 M
Solve any one question from Q.2(d) & Q.2(e)
2(d) Explain the following:
i) Effect of friction on the governor
ii) Isochronous conditions of governor
iii) Gyroscopic torque
iv) Expression for gyroscopic couple
7 M
2(e) Calculate the rage of speed of a porter governor which has equal arms of each 200mm long and pivoted on the axis of rotation . The mass of each ball is 5kg and the central load of the sleeve is 20kg. The radius of rotation of the ball is 100mm when the governor being to lift and 130mm when the governor is at maximum speed.
7 M

3(a) What is meant by balancing of rotating masses? List the effects of partial balancing of locomotives.
2 M
3(b) Discuss the effects of hammer below.
2 M
3(c) Differentiate between the unbalanced forces caused due to rotating and reciprocating masses.
3 M
Solve any one question from Q.3(d) & Q.3(e)
3(d) Discuss the following:
i) Static balancing and dynamic balancing.
ii) Swaying couple
iii) Can a single cylinder engine be fully balanced? Why?
iv) Why are the cranks of a locomotive, with two cylinders, placed at 90° to each other?
7 M
3(e) Four masses A, B, C and D revolves at equal radii and equally spaced along a shaft. The mass B is 7 kg and the radii of C and D make angles of 90° and 240° respectively with the radius of B. Find the magnitude of masses A, C and D and Angular position of A. So that the system may be completely.
7 M

4(a) Define the friction and friction circle, State types of friction.
2 M
4(b) Compare single plate and multi-plate clutches.
2 M
4(c) Discuss the concept of boundary and film lubrication.
3 M
Solve any one question from Q.4(d) & Q.4(e)
4(d) Find the power lost in friction at its operating temperature if, A 180 mm diameter shaft runs at 1800rpm, supporting a load of 18kn. The shaft runs in a bearing of length 1.5 times the shaft diameter. The clearing ratio is 0.015. The absolute viscosity of the oil is 11 cp.
7 M
4(e) A shaft running at 600 rpm is supported in a bearing of 60mm diameter and 60mm long. The viscosity of oil is 0.014 Pa S and the temperature of oil is 110°C. The radial clearance is 0.03mm. Determine temperature of still air in the bearing if there is no external cooling is provided. The temperature of still air in the room is 20°C.
7 M

5(a) Discuss selection of V-belts, ropes and chains for different applications.
2 M
5(b) Compare band break and block break.
2 M
5(c) Discuss centrifugal effect on belts.
3 M
Solve any one question from Q.5(d) & Q.5(e)
5(d) Select a V belt drive to transmit a power of kW from a shaft rotating at 1500 rpm to a parallel shaft to be run at 375rpm. The distance between the shaft centers is 500mm. The pitch diameter of the smaller grooved pulley can be taken to be 150mm. The factor of application is to be taken as 1.2.
7 M
5(e) Write short note on following:
i) Jump and cross-over shock
ii) Internal and external shoe brakes
7 M

More question papers from Dynamics of Machines