making some assumptions about what has been omitted from the question.
1. Assume you mean the body has mass of 1kg
2. Assume the only force acting on the body is one of 5 N, acting for 5s
3. Assume the body starts at rest.
Then we have constant accelleration:
so the velocity is:
displacement from initial position is:
Therefore with , , and , we have:
Therefore the work done is the force times the displacement