Correct Answer - Option 1 : Shaft rotating in a bearing
Concept:
Kinematic pair:
A kinematic pair or simply a pair is a joint of two links having relative motion between them.
Kinematics pair can be classified according to:
- Nature of contact
- Nature of relative motion
- Nature of mechanical constraint
Kinematic pairs according to Nature of Contact:
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Lower pair
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Higher pair
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A pair of links having surface or area contact between the members is known as a lower pair.
The contact surface of the two links is similar.
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When a pair has a point or line contact between the links, it is known as a higher pair.
The contact surface of the two links is dissimilar.
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E.g Nut turning on a screw, shaft rotating in a bearing, all pairs of slider-crank mechanism, universal joint etc.
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E.g Wheel rolling on a surface, cam and follower pair, tooth gears, ball and roller bearing etc.
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Nut turning on a screw - Surface contact - Lower pair
Wheel rolling on a surface - Line contact - Higher pair
Ball and roller bearing - Line contact - Higher pair
