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 :
You would feel weightless while falling from a roof.
Explanation:
To understand this, we need to explore the concept of “weightlessness” and how it relates to the forces acting on your body in different situations.
- While accelerating downward in an elevator:
When you are in an elevator that is accelerating downward, you experience a feeling of reduced weight, but you don’t technically feel completely weightless. Your body still has contact with the floor, and there is a normal force acting on you (although it’s reduced due to the acceleration). You will feel lighter, but you will still have weight. - While falling from a roof:
When you fall from a roof, both you and the object you are falling with (such as air) are in free fall. This means that you are accelerating towards the ground at the same rate due to gravity. During free fall, there is no contact force from the ground or any other surface, and you feel weightless because there is no reaction force opposing gravity. The sensation of weightlessness arises because your body is in free fall, and the normal force that usually supports you (like the ground or a floor) is absent. - While walking on the Moon:
On the Moon, gravity is weaker than on Earth (about 1/6th the strength). However, even though the gravitational pull is weaker, you still have weight, and you don’t feel weightless. The sensation of walking on the Moon might feel lighter compared to Earth, but you are still experiencing a gravitational force, so you’re not weightless. - While parachuting from an airplane:
When you parachute, at first, you are accelerating downward due to gravity. However, once you reach terminal velocity (when the upward air resistance balances the downward force of gravity), you stop accelerating. While you are falling and accelerating, you might feel some weightlessness, but once you stop accelerating, you no longer experience true weightlessness.
In summary, falling from a roof provides the true sensation of weightlessness because of the absence of any contact force and being in free fall.