Question

To know the rotations involved in the disks we use right handed coordinate system, in that system which of the following is followed (consider the mentioned axis to be positive)?

(a) Thumb is z-axis, fingers curled from x-axis to y-axis

(b) Thumb is x-axis, fingers curled from z-axis to y-axis

(c) Thumb is y-axis, fingers curled from x-axis to z-axis

(d) Thumb is z-axis, fingers curled from y-axis to x-axis

This question was addressed to me during an online interview.

The question is from Frictional Forces on Collar Bearing, Pivot Bearings and Disks in portion Friction of Engineering Mechanics

Answer 1

Right answer is (a) Thumb is z-axis, fingers curled from x-axis to y-axis

Explanation: As right handed coordinate system means that you are curling your fingers from positive x-axis towards y-axis and the thumb which is projected is pointed to the positive z-axis. Thus visualizing the same and knowing the basic members of the axis will not create many problems.