ME-503-B Dynamics of Machine - Jun 2025 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aFind the maximum and minimum speeds of a flywheel of mass $5200\text{ kg}$ and the radius of gyration $1.8\text{ m}$ when the fluctuation of energy is $100800\text{ Nm}$. The mean speed of the engine is $180\text{ r.p.m.}$
   How to answer

   • Define fluctuation of energy and mean speed relation
   • Formula $\Delta E = m k^2 \omega_{mean}^2 C_s$
   • Calculate coefficient of fluctuation
   • Find $N_{max}=N_{mean}(1+C_s/2)$ and $N_{min}=N_{mean}(1-C_s/2)$
2. 7 Marks
   bExplain turning moment diagram for four stroke cycle IC engine.
   How to answer

   • Define turning moment diagram
   • Explain four strokes: suction, compression, expansion, exhaust
   • Variation of torque vs crank angle
   • Need for flywheel in four-stroke IC engine
3. 7 Marks
   aDerive an expression for the height of Watt governor and prove that the height of the governor is inversely proportional to the square of the speed of governor.
   How to answer

   • Draw Watt governor geometry and forces on ball
   • Equilibrium of centrifugal force and weight
   • Derive $h = g/\omega^2 = 895/N^2$
   • Conclude $h \propto 1/N^2$
4. 7 Marks
   bThe lengths of the upper and lower arms of a Porter governor are $200\text{ mm}$ and $250\text{ mm}$ respectively. Both the arms are pivoted on the axis of the rotation. The central load is $150\text{ N}$, the weight of each wall is $20\text{ N}$ and the friction of the sleeve together with the resistance of the operating gear is equivalent to a force of $30\text{ N}$ at the sleeve. If the limiting inclinations of the upper arms to the vertical are $30^\circ$ and $40^\circ$, determine the range of the speed of the governor.
   How to answer

   • Write Porter governor speed formula with friction
   • Calculate height $h$ from arm lengths and $\theta=30^\circ,40^\circ$
   • Apply $N^2$ formula for max and min with $\pm F$
   • Obtain speed range $N_{min}$ to $N_{max}$
5. 7 Marks
   aWhat is the function of a governor? Give classification of governors.
   How to answer

   • Define governor and its function of speed regulation
   • Classify: centrifugal and inertia types
   • List Watt, Porter, Proell, Hartnell etc.
   • Brief use of each class
6. 7 Marks
   bCalculate the minimum speed of a Proell governor, which has equal arms each $200\text{ mm}$ and pivoted on the axis of rotation. The mass of each ball is $4\text{ kg}$ and the central mass on the sleeve is $20\text{ kg}$. The extension arms of the lower links are each $60\text{ mm}$ long and parallel to the axis when the minimum radius of the ball is $100\text{ mm}$.
   How to answer

   • Draw Proell governor geometry with extension arms
   • Relate ball radius, arm length and angle
   • Use equilibrium formula with central mass
   • Calculate minimum speed at $r=100$ mm
7. 7 Marks
   aExplain the following terms: Sensitiveness; isochronisms and hunting in connection with governor.
   How to answer

   • Define sensitiveness as speed range ratio
   • Define isochronism as constant speed condition
   • Define hunting as fluctuation due to oversensitivity
   • Give relevance to governor operation
8. 7 Marks
   bWhat is the difference between Portor governor and Proell governor?
   How to answer

   • Describe Porter governor construction with central load
   • Describe Proell governor with extended lower links
   • Compare ball position, sensitivity, height
   • State applications difference
9. 7 Marks
   aWhat is meant by the expression friction circle? Deduce an expression for the radius of friction circle in terms of radius of the journal and angle of friction.
   How to answer

   • Define friction circle concept in journal bearing
   • Show friction angle $\phi$ and radius relation
   • Derive $r_f = r \sin\phi$
   • State assumptions
10. 7 Marks
    bDescribe with a neat sketch the working of a single plate friction clutch.
    How to answer

    • Show construction: flywheel, pressure plate, friction plate
    • Explain engagement by spring force
    • Explain disengagement operation
    • Include neat labelled sketch
11. 14 Marks
    Explain the terms: Primary balancing, secondary balancing, Hammer blow, swaying couple, variation in tractive force.
    How to answer

    • Define primary vs secondary balancing forces
    • Explain hammer blow, swaying couple, tractive force variation
    • Give formulas for reciprocating unbalance
    • State effects in locomotives
12. 7 Marks
    aA conical pivot bearing supports a vertical shaft of $200\text{ mm}$ diameter. It is subjected to a load of $30\text{ kN}$. The angle of the cone is $120^\circ$ and the coefficient of friction is $0.025$, Find the power lost in friction when the speed is $140\text{ r.p.m.}$ assuming :

    1. i)uniform pressure
    2. ii)uniform wear
    How to answer

    • Write frictional torque for conical pivot: $T=2\mu WR/3$ etc.
    • Apply uniform pressure and uniform wear assumptions
    • Calculate $T$ and power $P=2\pi NT/60$
    • Compare both cases
13. 7 Marks
    bExplain working of conical clutch.
    How to answer

    • Show cone clutch components: driver, driven cones
    • Explain engagement by axial force and friction
    • Explain torque transmission advantage
    • Mention applications
14. 7 Marks
    aExplain working of internal expanding brake with the help of neat sketch.
    How to answer

    • Show drum, shoes, cam and springs layout
    • Explain outward expansion against drum
    • Explain braking torque generation
    • Include neat sketch
15. 7 Marks
    bWhat are the different types of Dynamometer?
    How to answer

    • Define dynamometer vs brake
    • List absorption and transmission types
    • Give examples: Prony, rope, hydraulic, eddy current
    • State use of each type