Theory of Machines online quiz - Set 02 - ObjectiveBooks

Theory of Machines online quiz - Set 02

Theory of Machines online Quiz: Set 02

Quiz Questions

01. In a steam engine, the earlier cut-off with a simple slide valve may be obtained by increasing the angle of advance of the eccentric but reducing the throw of the eccentric and keeping the steam lap and exhaust lap constant. This method will cause withdrawing or throttling of steam.

02. When two nonintersecting and non-coplanar shafts are connected by gears, the arrangement is known as helical gearing.

03. A body is said to vibrate with simple harmonic motion if its acceleration is proportional to the distance from the mean position.

04. According to law of gearing, the common normal at the point of contact between a pair of teeth must always pass through the pitch point.

05. A shaft of mass (mc) and stiffness (s) is fixed at one end and carries a mass (m) at the other end. The natural frequency of its transverse vibration is same as for longitudinal vibration.

06. When the connection between the elements forming a pair is such that the constrained motion is not completed by itself, but by some other means, the motion is said to be a completely constrained motion,

07. A governor is said to be isochronous when range of speed is zero for all radii of rotation of the balls within the working range, neglecting friction.

08. If the controlling force line for a spring controlled governor when produced intersects the Y-axis above the origin, then the governor is said to be unstable.

09. Whitworth quick return motion mechanism is an inversion of a double slider crank chain.

10. The virtual or equivalent eccentric for the Meyer's expansion valve is defined as an eccentric having such a length and angle of advance that will cause cut-off to take place at the same position, as is caused by the combined effect of main eccentric and expansion eccentric.

11. The tangential component of acceleration of the slider with respect to the coincident point on the link is called coriolis component of acceleration.

12. The equivalent length of a simple pendulum depends upon the distance between the point of suspension and the centre of gravity.

13. A flywheel is used to control the mean speed of an engine caused by the variations in load.

14. The instantaneous centres, which moves as the mechanism moves but joints are of permanent nature, are called permanent instantaneous centres.

15. The two links are said to have a pure rolling contact, when their instantaneous centre _________ on their point of contact.

16. 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.

17. The acceleration of the particle moving with simple harmonic motion is inversely proportional to the displacement of the particle from the mean position.

18. The distance between the centre of suspension and centre of percussion is equal to the equivalent length of a simple pendulum.

19. In forced vibrations, the magnitude of damping force at resonance is equal to the impressed force.

20. In vibration isolation system, if ω/ωn > 2, then for all values of damping factor, the transmissibility (i.e. the ratio of the force transmitted to the force applied) will be less than unity.

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