Question

Which of the following is true for centrifugal force causing unbalance?

(a) Direction changes with rotation

(b) Magnitude changes with rotation

(c) Direction and magnitude both change with rotation

(d) Direction and magnitude both remain unchanged with rotation

This question was addressed to me during a job interview.

The question is from Balancing of Rotating Masses in section Balancing of Rotating Masses of Machine Dynamics

Answer 1

The correct choice is (a) Direction changes with rotation

To explain I would say: Force acting radially outwards acts on the axis of rotation and is known as centrifugal force. This is a disturbing force on the axis of rotation, the magnitude of which is constant but the direction changes with the rotation of the mass.