Objective Questions on Theory of Machines - Set 22 - ObjectiveBooks

# Practice Test: Question Set - 22

1. The critical speed of a shaft in revolution per second is __________ as that of natural frequency of transverse vibration.
(A) Same
(B) Different
(C) Unpredictable
(D) None of these

2. Governor is used in automobile to
(A) Decrease the variation of speed
(B) Maximize the fuel economy
(C) Limit the vehicle speed
(D) Maintain constant engine speed

3. The following is the inversion of slider crank chain mechanism
(A) Whitworth quick return mechanism
(B) Hand pump
(C) Oscillating cylinder engine
(D) All of the above

4. The power from the engine to the rear axle of an automobile is transmitted by means of
(A) Worm and worm wheel
(B) Spur gears
(C) Bevel gears
(D) Hooke's joint

5. In an open pair, the two elements of a pair
(A) Have a surface contact when in motion
(B) Have a line or point contact when in motion
(C) Are kept in contact by the action of external forces, when in motion
(D) Are not held together mechanically

6. In a multiple V-belt drive, if one of the belts is broken, then we should replace
(A) The broken belt only
(B) All the belts
(C) The broken belt and the belts on either side of it
(D) None of the above

7. Flexible coupling is used because
(A) It is easy to disassemble
(B) It is easy to engage and disengage
(D) It prevents shock transmission and eliminates stress reversals

8. A cam with a roller follower would constitute following type of pair
(A) Lower pair
(B) Higher pair
(C) Open pair
(D) Close pair

9. The rotor of a ship rotates in clockwise direction when viewed from stern and the ship takes a left turn. The effect of gyroscopic couple acting on it will be
(A) To raise the bow and stern
(B) To lower the bow and stern
(C) To raise the bow and lower the stern
(D) To raise the stern and lower the bow

10. When the crank is at the outer dead centre, in a reciprocating steam engine, then the acceleration of the piston will be
(A) Ï‰² r {(n + 1)/n}
(B) Ï‰² r {(n - 1)/n}
(C) Ï‰² r {n/(n + 1)}
(D) Ï‰² r {n/(n - 1)}

11. The secondary unbalanced force due to inertia of reciprocating parts in a reciprocating engine is given by (where m = Mass of reciprocating parts, Ï‰ = Angular speed of crank, r = Radius of crank, Î¸ = Angle of inclination of crank with the line of stroke, and n = Ratio of the length of connecting rod to radius of crank)
(A) m.Ï‰².r sinÎ¸
(B) m.Ï‰².r cosÎ¸
(C) m.Ï‰².r (sin 2Î¸/n)
(D) m.Ï‰².r (cos 2Î¸/n)

12. If Ï‰/Ï‰n is very low for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach
(A) 0°
(B) 90°
(C) 180°
(D) 360°

13. The Klein's diagram is useful to find
(A) Displacement of various parts
(B) Velocity of various parts
(C) Acceleration of various parts
(D) Angular acceleration of various parts

14. Angular acceleration of a link can be determined by dividing the
(A) Centripetal component of acceleration with length of link
(B) Tangential component of acceleration with length of link
(C) Resultant acceleration with length of link
(D) All of the above

15. Which of the following mechanism is obtained from lower pair?
(A) Gyroscope
(B) Pantograph
(C) Valve and valve gears
(D) All of the above

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