Astudent weighing 500. newtons
stands on a spring scale in an
elevator. if the scale reads
520. newtons, the elevator must be

The elevator must be accelerating upward as the net force acting is upward.

Explanation:

Given:

Original weight of the student,

Reading on the spring scale is the normal reaction by the scale on the student and is given as,

The normal reaction acts in the upward direction while the weight of the student acts vertically downward.

Now, the magnitude of the normal reaction is greater than the magnitude of the weight. Therefore, the net force acting on the student is given as:

Therefore, the net force is acting vertically upward.

Now, as per Newton's second law, the direction of the net acceleration acting on a body is the same as the direction of the net force acting on it.

Thus, the elevator must be accelerating upward as the net force acting is upward.