Theory Of Machine - Study Mode
[#201] The ratio of the driving tensions for V-belts is __________ times that of flat belts. (Where β = Semi-angle of the groove)
Correct Answer
(C) cosecβ
[#202] In an open pair, the two elements of a pair
Correct Answer
(C) Are kept in contact by the action of external forces, when in motion
Explanation
Solution: >In an open pair: Option A: Have a surface contact when in motion. This is incorrect because surface contact typically describes a closed pair. Option B: Have a line or point contact when in motion. This is incorrect as it typically describes higher pairs, not open pairs. Option C: Are kept in contact by the action of external forces, when in motion. This is correct because, in an open pair, external forces are necessary to maintain contact between the elements. Option D: Are not held together mechanically. This is incorrect because while they are not mechanically locked, they are held together by external forces. Therefore, the correct answer is Option C: Are kept in contact by the action of external forces, when in motion .
[#203] In a single slider crank chain
Correct Answer
(D) Three are turning pairs and one is a sliding pair
[#204] The motion between a pair when limited to a definite direction, irrespective of the direction of force applied, is known as
Correct Answer
(A) Completely constrained motion
[#205] The primary unbalanced force is maximum when the angle of inclination of the crank with the line of stroke is
Correct Answer
(B) 0° and 180°