Terminal velocity & Zero G.

In summary, the conversation discusses two questions about the forces acting on passengers in an aircraft, specifically in a zero gravity situation and if passengers can be accelerated beyond their terminal velocity. The experts explain that in order to achieve a net zero force, all forces must either be zero or cancel each other out. This can be achieved by having the plane climb before taking a dive, allowing the passengers to feel weightless as the forces of the plane and gravity cancel out. The experts also mention that it is possible for passengers to be accelerated beyond their terminal velocity by adding an extra acceleration to counter the effects of friction. However, they advise against trying this at home.
  • #1
pipersam
1
0
Hello everyone,

I'm in great need of an expert answer and havn't been able to find much help at all, so I am hoping I have come to the best place.

I have two questions regarding forces acting apon passengers in an aircraft.

I would like to know how passengers would experience a zero gravitational force inside a pressurized aircraft, which would be in a fixed pitch 90 degee descent. Does this have anything to do with terminal velocity? Can it be achieved at all? I'm ignoring the structual limits of aircraft, and I don't want this to be a factor.

Which leads me on the my second question, can the passengers inside a pressurized aircraft be accelerated beyond their own terminal velocity?

I'm sorry if sound stupid in asking these questions, but I really would like a clear explanation.

Many thanks in advance,

Sam Crawford.
 
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  • #2
To answer the first question:
In order to achieve a net zero force on an object, all forces must either be zero or cancel each other out. If the plane were to do a climb (let's say about 45 degrees) before taking its dive, the passengers would feel weightless as the plane began to reach its maximum height (the plane would have to have slow down its turbines and begin pointing down gradually). What will happen then is that the forces of the plane on the passengers will zero out. Even though there still is the gravity from the Earth, the passengers will float around in the plane (because the plane and the passengers will be falling at the same speed) (the passengers' point of reference would be the plane). In order to experience a zero force at a 90 degree dive, the plane's turbines would have to be off instead of slowed down during the climb. The plane can only accelerate due to gravity. This doesn't have to do much with the terminal velocity of the plane (assuming that the aerodynamics and large mass allow this assumption to be true).
To answer the second question:
Since the airplane is accelerating downwards due to gravity, it is then accelerating everything inside of it. Think of driving in a car with the windows down, as you accelerate you don't feel a sudden rush of air. This is because the car is accelerating all of its contents, even the air. So, the passengers would be able to go faster in a falling plane than in free fall themselves.
 
  • #3
Not sure if I'm understanding your question correctly, but here's an attempt.

A "zero gravitational field" would feel just like the one you feel when you are in the ISS, for example. Technically, you are not in "zero gravity", you are simply free-falling towards the earth. Since everything around you falls equally fast, it seems like there is no gravity at all. Of course, the difference is that the ISS will keep falling around the Earth while the passengers in a plane will eventually hit the ground. However, planes are used, for example to train astronauts. An aircraft there flies along a parabolic trajectory, the downward part of which corresponds to an acceleration of 9,8.. m/s/s towards the Earth - effectively a free fall.

Assuming that you mean by "terminal velocity" the velocity one would eventually obtain (due to the effects of friction), it is of course possible to accelerate beyond that. All you need is to add an extra acceleration to counter the friction. For example, free-fall until you reach the terminal velocity, then switch on a rocket booster which is pointed upward, so you get accelerated downward. However, I strongly suggest not trying that at home :P
 

1. What is terminal velocity?

Terminal velocity is the maximum velocity that a falling object can reach when it is no longer accelerating due to the opposing force of air resistance. It is the point at which the force of gravity is equal to the force of air resistance, resulting in a constant downward velocity.

2. How is terminal velocity calculated?

Terminal velocity can be calculated using the equation Vt = √(2mg/ρAC), where Vt is terminal velocity, m is the mass of the object, g is the acceleration due to gravity, ρ is the density of the fluid (air), A is the projected area of the object, and C is the drag coefficient.

3. What factors affect terminal velocity?

The main factors that affect terminal velocity are the mass, size, and shape of the object, as well as the density of the fluid it is falling through and the force of gravity. Objects with larger surface areas or lower densities will have lower terminal velocities.

4. How does zero gravity affect terminal velocity?

In a zero gravity environment, such as in space, there is no air resistance to slow down an object's fall. Therefore, the concept of terminal velocity does not apply in this situation. Objects will continue to accelerate until they reach a constant velocity determined by the force of gravity.

5. Can an object experience zero gravity on Earth?

No, it is not possible for an object to experience true zero gravity on Earth as there is always some level of gravitational force acting upon it. However, in certain conditions such as in free fall or in an airplane performing a parabolic flight, an object can experience a temporary state of weightlessness, which may be perceived as zero gravity.

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