Question

Consider a person standing in an elevator that is moving at constant speed upward. The person, of mass m, has two forces acting upon him, the downward force m g due to gravity, and the upward supporting force n exerted by the floor of the elevator. In this case, which of these two forces has the smaller magnitude?

Answer 1

Answer:

The force of gravity

Explanation:

Remember that when sometthing is moving there is always several forces acting on the object, in this case, the gravity is pulling the mass of the person standing downward and the floor of the elevator ispulling upward, the direction of the movement will dictate which force is greater than the other, as the person is moving upward that is the greater force, the force of gravity is the smaller magnitude.

Answer 2

Answer:

The weight of the person has a smaller magnitude.

Explanation:

For an observer in inertial frame of reference for the person in the elevator Newton's Second Law can be written as

Normal reaction acts upwards

Weight acts downwards

$\sum F_{v}=ma_{v}\\\\N-mg=m\times a_{v}\\\\m\times a_{v}> 0\\\\\therefore N-mg> 0\\\\\therefore N> mg$

Here

N is the normal reaction force

mg is the weight of the person

g is acceleration due to gravity