In a tug of war the tension in the rope that A and B are pulling is 1956 N. What is the work done by A if he pulls B by 2.8 m?

When A and B are pulling on the rope the tension in the rope is
the sum of the forces with which each of A and B is pulling the rope. To be able to pull the rope
towards himself the force that either A or B has to apply should be equal to the tension in the
rope.

Here we are given that the tension in the rope is 1956 N. A is
able to pull B by 2.8 m.

The work done by A in doing so is equal to
force*distance.

Using the values given we have work = force*distance
= 1956*2.8 = 5476.8 J

The required value of the work
done by A is 5476.8 J.