In which of the following cases would you feel weightless?
while accelerating downward in an elevator
while falling from a roof
while walking on the Moon
while parachuting from an airplane
The correct answer and explanation is :
The correct answer is: while falling from a roof.
Explanation:
When we talk about feeling “weightless,” we typically refer to the sensation that occurs when an object or a person is in free fall, experiencing no support force, such as the force exerted by a floor or ground. In these scenarios, the person or object is essentially in free fall, and their acceleration due to gravity matches the rate of acceleration of the Earth’s gravitational field. This causes them to feel weightless.
Let’s break down each scenario to clarify why falling from a roof is the correct situation:
- While accelerating downward in an elevator:
In this case, you might feel lighter if the elevator is accelerating downward, as the force you feel from the floor (the normal force) decreases. However, you are not truly weightless because gravity still pulls you downward, and the elevator is providing a supporting force. You would not feel completely weightless in this situation; you would just feel lighter, but the sensation is different from true weightlessness. - While falling from a roof:
This is the situation where you would feel truly weightless. When you fall, your body is in free fall, and gravity is pulling you downward at the same rate that you are accelerating. In this moment, there is no ground or other surface exerting an opposing force on your body, which results in the sensation of weightlessness. The feeling of weightlessness is not the absence of gravity, but rather the absence of the support force you normally feel when standing on the ground. - While walking on the Moon:
On the Moon, you would weigh much less due to the weaker gravitational pull (about 1/6th of Earth’s gravity). However, you would still feel the gravitational force, so you would not experience weightlessness. Instead, you would feel much lighter but still under the influence of gravity. - While parachuting from an airplane:
While parachuting, there is a sense of “free fall” initially, but once the parachute opens, you experience upward drag force, which prevents you from falling freely. Therefore, you do not feel truly weightless; instead, you feel the resistance from the parachute and a reduced acceleration due to gravity.
Thus, falling from a roof is the best example of feeling weightless.