# Theory of machines – Section 2

21. Which of the following is a higher pair?

A. Belt and pulley
B. Turning pair
C. Screw pair
D. Sliding pair

Correct Answer: A. Belt and pulley

22. When the belt is stationary, it is subjected to some tension known as initial tension. The value of this tension is equal to the

A. tension in the tight side of the belt
B. tension in the slack side of the belt
C. sum of the tensions on the tight side and slack side of the belt
D. average tension of the tight side and slack side of the belt

Correct Answer: D. average tension of the tight side and slack side of the belt

23. In a force-closed pair, the two elements of a pair are not held together mechanically.

A. Agree
B. Disagree

24. Maximum fluctuation of energy in a flywheel is equal to (where I = Mass moment of inertia of the flywheel, E = Maximum fluctuation of energy, CS = Coefficient of fluctuation of speed, and ω = Mean angular speed = A. Iω(ω1 – ω2)
B. Iω2CS
C. 2ECS
D. all of these

Correct Answer: D. all of these

25. The Coriolis component of acceleration acts

A. along the sliding surface
B. perpendicular to the sliding surface
C. at 45° to the sliding surface
D. parallel to the sliding surface

Correct Answer: B. perpendicular to the sliding surface

26. The module is the reciprocal of diametral pitch.

A. True
B. False

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

A. stable
B. unstable
C. isochronous
D. none of these

28. In a reciprocating steam engine, when the crank has turned from the inner dead center through an angle θ, the angular acceleration of the connecting rod is given by 29. 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.

A. Right
B. Wrong