Question

The instantaneous centres which vary with the configuration of the mechanism, are called

(a) permanent instantaneous centres

(b) fixed instantaneous centres

(c) neither fixed nor permanent instantaneous centres

(d) none of the mentioned

This question was posed to me in semester exam.

I'm obligated to ask this question of Velocity of a point Link on a Link By Instanteneous Centre Method topic in division Velocity in Mechanisms of Machine Kinematics

Answer 1

Correct option is (c) neither fixed nor permanent instantaneous centres

To elaborate: Fixed instantaneous centres remain in the same place for all configurations of the mechanism. The permanent instantaneous centres move when the mechanism moves, but the joints are of permanent nature. Neither fixed nor permanent instantaneous centres vary with the configuration of the mechanism.