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:
To understand why you would feel weightless in this scenario, we first need to define what it means to feel weightless. Weightlessness occurs when there is no normal force acting on you. This is the force that pushes against you when you stand on the ground or sit in a chair. When you feel weightless, it’s because the normal force is absent or effectively negated.
- While accelerating downward in an elevator:
In this situation, you’re still in contact with the floor of the elevator, and gravity is pulling you down. The elevator’s downward acceleration will reduce the normal force, but you will not feel completely weightless because some normal force is still present. You might feel lighter, but not weightless. - While falling from a roof:
When you fall, you’re in a state of free fall, which means both you and your surroundings (in this case, the air) are accelerating downward due to gravity. Since you are falling along with the roof or the object you’re attached to, there is no force pushing back on you. Essentially, you feel weightless because there is no normal force to oppose your weight. This is often referred to as “free fall.” - While walking on the Moon:
On the Moon, gravity is much weaker than on Earth (about 1/6th of Earth’s gravity). While you would feel less weight compared to Earth, there is still gravity acting on you. As a result, you would still feel some weight, though it would be significantly reduced. You wouldn’t experience true weightlessness, but rather reduced weight. - While parachuting from an airplane:
During a parachute jump, you initially experience free fall. However, once the parachute opens, it slows your fall considerably. Before the parachute deploys, you might feel weightless, but as you decelerate and the parachute creates a normal force, you would no longer feel weightless.
In conclusion, while falling from a roof is the scenario in which you would experience true weightlessness because there is no normal force acting on you during free fall.