Question

For design of ordinary machinery, value of journal friction can be taken as

(a) 0.008 to 0.02

(b) 0.07 to 0.15

(c) 0.05 to 0.80

(d) none of the mentioned

This question was addressed to me in an international level competition.

This intriguing question originated from Limiting Angle of Friction in chapter Friction of Machine Kinematics

Answer 1

The correct choice is (a) 0.008 to 0.02

To elaborate: For very low velocities of rotation, high loads, and with good lubrication can be taken as 0.07 to 0.15.

For design of ordinary machinery, value of journal friction can be taken as 0.008 to 0.02.