Question

Match the following group-1 items (Kinematic Pairs) with group-2 items (Examples) and select the correct options:

1.	Revolute pair	A.	Ball-bearing
2.	Helical pair	B.	Ball and socket
3.	Rolling pair	C.	Lathe spindle in the headstock
4.	Globular pair	D.	Motion between the bolt and fixed nut

1. 1-D, 2-A, 3-C, 4-B
2. 1-B, 2-D, 3-A, 4-C
3. 1-C, 2-D, 3-A, 4-B
4. 1-A, 2-C, 3-D, 4-B

Answer 1

Correct Answer - Option 3 : 1-C, 2-D, 3-A, 4-B

Explanation:

Revolute Pair (R-pair): A revolute pair has one degree of freedom and permits a rotational motion about an axis. A revolute pair is often called a pin joint. 

• Example: Lathe spindle in the headstock.

Helical Pair (H-pair) A helical pair has one degree of freedom and permits rotational and translational motion. These motions are, however, related by the pitch value of the helical pair. A helical pair is often called a screw pair

• Example: Motion between the bolt and fixed nut

​Rolling pair: A pair of two links having a rolling motion relative to each other is called rolling pair

• Example: Ball bearing, contact between the ball or roller, etc.

Globular or Spherical pair:  In a spherical pair, one link is constrained to swivel in or about the other fixed point. 

• Example: Ball in the socket

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1. Sliding pair: In this pair two links are so connected that one is constrained to have sliding motion relative to another e.g. crosshead and guide.
2. Turning pair: In this pair two links are so connected that one is constrained to turn or revolve about a fixed axis of another e.g. crankshaft turning in a bearing