Which of the following is a turning pair?
A
Piston and cylinder of a reciprocating steam engine
B
Shaft with collars at both ends fitted into a circular hole
C
Lead screw of a lathe with nut
D
Ball and a socket joint
Correct Answer: Shaft with collars at both ends fitted into a circular hole
When the two elements of a pair are constrained in such a way that one can only turn or revolve about a fixed axis of another link, the pair is known as turning pair.