Question

A person stands in an elevator. The elevator starts from rest and travels from the first floor to the fifth floor of the building. Which of the following forces has a magnitude equal to the person's weight during the entire elevator ride?

The gravitational force exerted by the elevator on the person.
The gravitational force exerted by the person on Earth.
The normal force exerted by the elevator on the person.
The normal force exerted by the person on the elevator.

Answer 1

The gravitational force exerted by the person on Earth has a magnitude equal to the person's weight throughout the elevator ride, as this force remains constant regardless of the elevator's movement.

Step-by-step explanation:

The force that has a magnitude equal to the person's weight during the entire elevator ride is the gravitational force exerted by the person on Earth. Regardless of the elevator's movement, the person's weight, represented by the gravitational force that Earth exerts on the person, remains constant. According to Newton's third law, this force is matched by an equal and opposite force exerted by the person on the Earth.

However, the normal force exerted by the elevator on the person can vary depending on the acceleration of the elevator. If the elevator is accelerating upwards, the normal force is greater than the person's weight, and if it is accelerating downwards, it is less. When the elevator moves at a constant speed or is at rest, the normal force equals the person's weight.