A 615 N student standing on a scale in an elevator notices that the scale reads 645 N.  From this information, the student knows that the elevator must be moving upward. true or false

1 Answer | Add Yours

jeew-m's profile pic

jeew-m | College Teacher | (Level 1) Educator Emeritus

Posted on

We can use Newtons second law of motion here.

Mass of student `= 615/9.81 = 62.7`


Weight of student act downward and the reaction of his weight act upward on the scale.

`uarr F = ma`

`645-615 = 62.7*a`

            ` a = 0.478m/s^2`


Since the acceleration is a positive value the elevator goes upward.

It is true.

We’ve answered 317,740 questions. We can answer yours, too.

Ask a question