Final answer:
When you are 40,000 feet up in the air on an airplane, your weight does not change. Weight is the force due to gravity acting on an object, and it remains the same regardless of altitude.
Step-by-step explanation:
When you are 40,000 feet up in the air on an airplane, your weight does not change. Weight is the force due to gravity acting on an object, and it remains the same regardless of altitude. However, you may feel lighter due to the absence of air resistance and the sensation of weightlessness when the plane accelerates or descends rapidly.
For example, when an airplane descends rapidly, it creates a feeling of weightlessness because both the airplane and you are falling at the same rate. This is similar to being in a freely falling elevator.