Question

A ball and socket forms a

• A. Turning pair
• B. Rolling pair
• C. Screw pair
• D. Spherical pair

Hint:

Think of the human shoulder or hip joint, which are biological ball-and-socket joints allowing rotation in three perpendicular planes. This is a spherical pair.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Kinematic pairs are classified based on the type of relative motion between two link members.

Step 3: Detailed Explanation:
Let us review the characteristics of the different kinematic pairs:
1.

Turning pair: Permits only a relative angular rotation about a fixed axis (1 degree of freedom).
2.

Rolling pair: Allows one link to roll over another without slipping.
3.

Screw pair: Combines rotation and translation along the same axis using a screw thread mechanism.
4.

Spherical pair: Allows one link to rotate in three dimensions relative to another about a fixed spherical center point (3 degrees of freedom).
A ball and socket joint is a classic example of a spherical pair, permitting rotational motion in any spatial direction while restricting relative translation.

Step 4: Final Answer:
The correct option is 4, which corresponds to Spherical pair.