The original question has been answered, if you're arguing what wieght is, I posted a science dictionary defenition eariler. Use that one to see what mass, graviry, tension, and all the rest of the terms are if you need to.

Near the Earths surface you (and all objects) will always have a constant wieght. This is because gravity is constant and the mass is constant.

If a body is stationary the net force is always zero (ignoring rotationary forces).

In different mediums, the objects will feel lighter in more dense mediums as the upthrust (which will always be in the direction opposite to the weight) will partly counteract the wieght. In a sufficiently dense medium, the object will float, because it has a net force of zero. In fact it's weight is still constant, it is just totally counteracted by the upthrust. Obviously this balance is ruined as soon as you lift the body out of the liquid or push in into the liquid.

When something is being hung the object is still stationary hence it will have a net force of zero, but it will still weight the same. If you are being hung and you are taken to be part of the hanging contraption too, then the enitre contraption will have a net force of zero (as it is stationary (neither floating into the air nor sinking into the ground)), it's weight will have changed because your mass has been added onto it's mass thereby changing it's mass. It's net force remains zero because the ground beneath it will simply exert a larger counter force.