A particle is moving with displacement  under the action of force . The work done by the force in an arbitrary unit is:

The question seems to be incomplete. The displacement and force are not specified. However, I can explain how to calculate the work done by a force.

The work done by a force on a particle is given by the dot product of the force vector and the displacement vector.

Here are the steps to calculate it:

1. Identify the force vector and the displacement vector. These vectors should be given in the problem.

2. Calculate the dot product of these two vectors. The dot product of two vectors A and B is given by A.B = |A||B|cosθ, where |A| and |B| are the magnitudes of A and B, and θ is the angle between A and B.

3. The result of the dot product is the work done by the force.

Please provide the specific force and displacement vectors so I can help you calculate the work done.