A student weighing 500. N stands on a spring scale in an elevator. If the scale reads 520. N, the elevator must be

moving upward at constant speed

The force that the student exerts on the scale is the reaction force of the normal force that the elevator exerts on the student. N = 520. NSince the weight is 500 N which is less than the normal force, the net force of the student is 20 N upwards. Thus, the elevator must be accelerating upward.