Question

Why are objects weightless, when they are in free fall ?

Answer 1

Weight (or rather the apparent weight, i.e. the weight felt by the body) of a body is actually the reaction force that it feels from the floor on which the body is standing or the rope from which it is hanging (in the second case the reaction is tension). During a free fall a body makes no contact with anything so no question of such reaction force arises. It is actually not weightless, but feels itself to be weightless.