What was the change in internal energy (chemical energy plus thermal energy) of the person pulling the block?

The internal energy is the sum of the heat absorbed or emitted and the work done.

The question is incomplete but I will try  to help you as much a possible. The term internal energy refers to all the energy that is contained in the system.

From the first law of thermodynamics, the internal energy is the sum of the heat absorbed or emitted and the work done. Hence we can write;

U = q + w.

Learn more about internal energy:link

learn it on the intertant so you can solve

in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.