A person is standing on a scale placed on the floor of an elevator. At time t1, the elevator is at rest and the reading on the scale is 500N. At a later time t2, the person is still standing on the scale and the reading on the scale is 400N . Based on the scale readings, which of the following statements about the motion of the elevator could be true at time t2?

a. The elevator is moving upward at constant speed.
b. The elevator is moving upward and slowing down.
c. The elevator is moving downward at constant speed.
d. The elevator is moving downward and slowing down.
e. The elevator is at rest.

This is about weight of humans in an elevator.

C. The elevator is moving downward at constant speed.

When one steps on a scale inside an elevator that is in motion accelerating upwards, such a person will feel more weight because the floor of the elevator is exerting a force on your feet and therefore the scale will read a higher weight than it will when the elevator is at rest. Now, on the opposite side, when the elevator in motion accelerating downward, you will feel a lot lighter than when you were going upwards in the elevator. This is because the elevator's acceleration is downward and it is now equal to the acceleration due to gravity which is constant. This implies that you are in a free fall with the elevator since the scale no longer exerts exert any force in a free fall. Thus, the weight the scale will read will be lesser than the actual weight of the person.Thus, we can conclude that the elevator is moving downward at constant speed.

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the following statements about the motion of the elevator could be true at time t2 is

c. The elevator is moving downward at constant speed.

Explanation:

Under given situation, the elevator is at rest and the reading on the scale is 500N.After some time t2, the person is still standing on the scale and the reading on the scale is 400N . It is because if you stand on a scale in an elevator which is accelerating upward, your body will feel heavier because the elevator's floor pressure which presses harder on your feet, and this is why the scale will show a higher reading than the time when the elevator is at rest.Similarly on the other hand, when the elevator accelerates downward, your body will feel lighter. The force which is exerted by the scale is called as the apparent weight; which means it does not change with constant speed.Applying Newton's second law, which concludes about this particular statement about force exerted on a body when at rest and when in motion.

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