This is a difficult question - smart people only.?

Question

When decelerating, during flight, from a fast cruise speed toward a slow approach speed, I notice that as the rate of decrease in speed constantly increases, the sensation is one of deceleration. But once the rate of deceleration is stabilized, constant, and unchanging, the sensation becomes one of hanging there presumably at a steady speed - there is no perception of deceleration (or even of speed for that matter) even though still decelerating. Even more deceptive, if slight control changes are made which cause a constantly decreasing rate of deceleration, the sensation becomes one of acceleration even though the aircraft is still decelerating (but at a decreasing change in the rate of the decreasing change of speed). Why is that?

Answer 1

Acceleration indicates the value of velocity at a point in time during the airplane travel.

Acceleration does not exist by itself because to every acceleration there is a reactive acceleration.(Newton 3rd law)


Our body is very sensitve to pressure changes;therefore if the changes are very brusk we would feel it very quickly with our stomach.
If the Jet plane descent is done very gradually with small changes one would not feel any acceleration or even detect it except if you looked out the window .

Answer 2

The key word in your question is 'sensation'. We have a limited capacity to sense acceleration. And there is no way to sense speed without comparison to nearby objects. You can sense the acceleration of an airplane during takeoff. You can sense the decrease of that acceleration. But you're really not equipped to sense when that acceleration happens to cross zero relative to the earth, or even goes negative. Further, the direction of acceleration is changing continuously.

My most vivid experience of that was skiing during a snowstorm. I couldn't see anything but white. As the terrain turned uphill, I could not tell when I stopped moving forward and started moving backward.

Answer 3

"If slight control changes are made which cause a constantly decreasing rate of deceleration, the sensation becomes one of acceleration"..........

If you're turning, could this be becuase of centripetal acceleration? Perhaps you are accelerating, but the body of the plane (relative to the point of rotation) is not.

Answer 4

The deceleration is a force like that of gravity. Your body becomes accustomed to the force and it becomes less noticable. Slight changes in acceleration or deceleration cause you to feel it as a force, much the same as gravity.

Answer 5

it happens coz sometimes pilots land the plane with zero power i.e. they glide the plane and after touchdown the start the reverse thrust
while landing with engines on u don't get the feeling of hanging in air

Answer 6

It accelerates to keep the pitch of the nose acceptable while in decent.

Answer 7

physics

Answer 8

inertia, inertia, inertia and inertia