We are told that an elevator falls freely, which means that the only force acting upon it is its weight. The weight is defined as:
Where "m" is the mass and "g" is the acceleration of gravity. Replacing the given values:
![\begin{gathered} W=(100\operatorname{kg})(10(m)/(s^2)) \\ W=1000N \end{gathered}]()
Therefore, the force that acts upon the elevator is 1000N.