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  • Question

  • In a vibrating system, if the actual damping coefficient is 40 N/m/s and critical damping coefficient is 420 N/m/s, then logarithmic decrement is equal to


  • Options
  • A. 0.2
  • B. 0.4
  • C. 0.6
  • D. 0.8

  • Correct Answer
  • 0.6 

    • Theory of machines problems

    Search Results

    • 1. Shock resisting steels should have

    • Options
    • A. low wear resistance
    • B. low hardness
    • C. low tensile strength
    • D. toughness
      • Discuss
    • 2. Malleable cast iron is produced

    • Options
    • A. by adding magnesium to molten cast iron
    • B. by quick cooling of molten cast iron
    • C. from white cast iron by annealing process
    • D. none of these
      • Discuss
    • 3. Specify the sequence correctly

    • Options
    • A. Grain growth, recrystallisation, stress relief
    • B. Stress relief, grain growth, recrystallisation
    • C. Stress relief, recrystallisation, grain growth
    • D. Grain growth, stress relief, recrystallisation
      • Discuss
    • 4. Iron-carbon alloys containing 1.7 to 4.3% carbon are known as

    • Options
    • A. eutectic cast irons
    • B. hypo-eutectic cast irons
    • C. hyper-eutectic cast irons
    • D. none of these
      • Discuss
    • 5. A small percentage of boron is added to steel in order to

    • Options
    • A. increase hardenability
    • B. reduce machinability
    • C. increase wear resistance
    • D. increase endurance strength
      • Discuss
    • 6. When a body moves with simple harmonic motion, the product of its periodic time and frequency is equal to

    • Options
    • A. zero
    • B. one
    • C. ?/2
    • D. ?
      • Discuss
    • 7. In vibration isolation system, the transmissibility will be equal to unity, for all values of damping factor, if ?/?n is

    • Options
    • A. equal to one
    • B. equal to 2
    • C. less than 2
    • D. greater than 2
      • Discuss
    • 8. For high speed engines, the cam follower should move with

    • Options
    • A. uniform velocity
    • B. simple harmonic motion
    • C. uniform acceleration and retardation
    • D. cycloidal motion
      • Discuss
    • 9. The rotor of a ship rotates in clockwise direction when viewed from stern and the ship takes a right turn. The effect of gyroscopic couple acting on it will be to raise the stern and lower the bow.

    • Options
    • A. Agree
    • B. Disagree
      • Discuss
    • 10. For a twin cylinder V-engine, the crank positions for primary reverse cranks and secondary direct cranks are shown in the below figure. The engine is a

    • Options
    • A. 30° V-engine
    • B. 60° V-engine
    • C. 120° V-engine
    • D. 150° V-engine
      • Discuss

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