The free body diagram of the forces on the person standing on a elevator is shown in the image attached.
What are the forces acting on a person in an elevator?
The free body diagram for a person with mass m standing on a scale in an elevator includes the following forces.
The weight of the person( W), acting downwards.
The force of the scale on the person, (Fn), acting upwards.
For an equilibrium situation, the force of the scale on the person is equal in magnitude and opposite in direction to the weight of the person. So in such situation, the net force on the person is zero, resulting in a constant velocity.