Pseudo force comes in effect when the frame of reference has started acceleration compared to a non-accelerating frame. The force F does not arise from any physical interaction between two objects, but rather from the acceleration 'a' of the non-inertial reference frame itself.

Why do we use pseudo force?

A fictitious force (also called a pseudo force, d'Alembert force, or inertial force) is a force that appears to act on a mass whose motion is described using a non-inertial frame of reference, such as an accelerating or rotating reference frame.

What is the work done by pseudo force?

The work done by a pseudo force is zero as it acts to appear on the body.