Mechanical Theory of Machines - Set 30 - ObjectiveBooks

Practice Test: Question Set - 30

1. Critical damping is a function of
(A) Mass and stiffness
(B) Mass and damping coefficient
(C) Mass and natural frequency
(D) Damping coefficient and natural frequency

2. Whirling speed of the shaft is the speed at which
(A) Shaft tends to vibrate in longitudinal direction
(B) Torsional vibrations occur
(C) Shaft tends to vibrate vigorously in transverse direction
(D) Combination of transverse and longitudinal vibration occurs

3. In a hydrodynamic journal bearing, there is
(A) A very thin film of lubricant between the journal and the bearing such that there is contact between the journal and the bearing
(B) A thick film of lubricant between the journal and the bearing
(C) No lubricant between the journal and the bearing
(D) A forced lubricant between the journal and the bearing

4. Which of the following statement is correct for gears?
(A) The addendum is less than the dedendum
(B) The pitch circle diameter is the product of module and number of teeth
(C) The contact ratio means the number of pairs of teeth in contact
(D) All of the above

5. The pitching of a ship produces forces on the bearings which act __________ to the motion of the ship.
(A) Vertically and parallel
(B) Vertically and perpendicular
(C) Horizontally and parallel
(D) Horizontally and perpendicular

6. The periodic time of one oscillation for a simple pendulum is
(A) 2π. √(g/l)
(B) (1/2π). √(g/l)
(C) 2π. √(l/g)
(D) (1/2π). √(l/g)

7. The radial distance from the top of a tooth to the bottom of a tooth in a meshing gear, is called
(A) Dedendum
(C) Clearance
(D) Working depth

8. The radial distance of a tooth from the pitch circle to the bottom of the tooth is called
(A) Dedendum
(C) Clearance
(D) Working depth

9. Which of the following is a higher pair?
(A) Belt and pulley
(B) Turning pair
(C) Screw pair
(D) Sliding pair

10. The frictional torque transmitted in a conical pivot bearing with assumption of uniform pressure is __________ as compared to uniform wear.
(A) Less
(B) More
(C) Same
(D) None of these

11. Two pulleys of radii r₁ and r₂ and at distance x apart are connected by means of a cross belt drive. The length of the belt is
(A) π (r₁ + r₂) + [(r₁ + r₂)²/x] + 2x
(B) π (r₁ + r₂) + [(r₁ - r₂)²/x] + 2x
(C) π (r₁ - r₂) + [(r₁ - r₂)²/x] + 2x
(D) π (r₁ - r₂) + [(r₁ + r₂)²/x] + 2x

12. In a radial cam, the follower moves
(A) In a direction perpendicular to the cam axis
(B) In a direction parallel to the cam axis
(C) In any direction irrespective of the cam axis
(D) Along the cam axis

13. In a steam engine, the earlier cut-off with a simple slide valve may be obtained by increasing the steam lap and the angle of advance of the eccentric but keeping constant the travel and lead of the valve, this method will
(A) Cause withdrawing or throttling of steam
(B) Reduce length of effective stroke of piston
(C) Reduce maximum opening of port to steam
(D) All of these

14. A higher pair has__________.
(A) Point contact
(B) Surface contact
(C) No contact
(D) None of the above

15. What is the number of instantaneous centers for an eight link mechanism?
(A) 15
(B) 28
(C) 30
(D) 8

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