Question

A person weighing 490N stands on a scale in an elevator. What does the scale read (normal force) when the elevator rises at a constant velocity of 5 m/s?

Answer 1

490 N

Step-by-step explanation:

The elevator is rising at constant velocity: this means the acceleration of the system is zero, so according to Newton's second law, the net force on the system is also zero:

`F_(net) = ma =0`

There are two forces acting on the person standing on the scale:

- its weight, downward, whose magnitude is W=490 N

- The normal force of the scale on the person, N, which is upward

Since the net force must be zero, we have:

`W-N=0`

From which we find the normal force:

`N=W=490 N`