A ball and a socket forms a

Solution (By Examveda Team)

Definition:
A ball and socket joint is a type of mechanical connection in which a spherical ball fits into a hollow socket, allowing rotational movement in multiple directions. This joint mimics the movement seen in the human shoulder or hip joint.

Correct Answer: Option D – Spherical pair

Explanation:
A spherical pair is a type of kinematic pair in which one link (the ball) is enclosed within another link (the socket), allowing rotational motion in three degrees of freedom: pitch, yaw, and roll. This means the ball can rotate freely in all directions inside the socket, but it cannot translate.

This type of joint is often used in mechanisms that require multi-directional motion and flexibility, such as robotic arms, automotive suspensions, and anatomical models.

The ball and socket joint is classified as a lower pair because there is surface contact between the ball and the socket throughout their motion.

Why other options are incorrect:
Option A: Turning pair – A turning pair allows rotation only about one fixed axis. The ball and socket allows rotation about multiple axes, so it is more complex than a turning pair.
Option B: Rolling pair – Rolling pairs involve rolling contact between two bodies, such as a wheel on a surface. The ball and socket does not involve rolling but rather rotational motion with surface contact.
Option C: Screw pair – A screw pair combines rotational and translational motion with a helical constraint, which is not the case in a ball and socket joint.

Conclusion:
A ball and socket joint provides multi-directional rotational motion and fits the definition of a spherical pair. Hence, the correct answer is Option D.