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:
Weightlessness occurs when there is no normal force acting on an object, meaning that the object is in free fall. In this condition, a person does not feel their weight because there is no external force (like the ground or a chair) pushing against them. Let’s analyze each scenario:
- While accelerating downward in an elevator
- If the elevator is accelerating downward, you will feel lighter, but not completely weightless unless the elevator is in free fall (falling with the acceleration of gravity, 9.8 m/s²). If the elevator were in complete free fall (which is rare), then you would experience weightlessness.
- While falling from a roof (Correct Answer)
- When falling freely from a roof, both you and your surroundings are accelerating downward at the same rate due to gravity (9.8 m/s²). There is no normal force acting on you, and you experience true weightlessness, similar to astronauts in orbit.
- While walking on the Moon
- On the Moon, gravity is weaker than on Earth (about 1/6th of Earth’s gravity), so you feel lighter, but you are still experiencing weight due to the Moon’s gravitational pull. This is not true weightlessness.
- While parachuting from an airplane
- Before opening the parachute, you are in free fall and experience weightlessness. However, as soon as air resistance builds up, your descent slows, and you feel a force acting on you again. Once the parachute opens, you no longer feel weightless because air resistance provides a counteracting force.
Thus, falling from a roof is the scenario where you truly experience weightlessness.