Hyperloop without acceleration feeling I have a question about hyperloop.
Is it possible to create a hyperloop with high acceleration and that the passengers dont feel the acceleration, theoretically speaking?
And is a situation possible you dont feel acceleration?
 A: In fact yes it's possible in theory, sorry to disagree with some other posts. 
Because of the absence of tidal forces due to earth's gravity on the human scale you don't feel acceleration due to gravity. When you fall you feel a reduction in acceleration against gravity. When in free fall you experience no acceleration although external observers will see you speed up as you follow a gravitational geodesic.
Therefore a frame of reference of vehicle in free fall can be manipulated with artificial acceleration of 1g in any desired direction and the force felt by occupants will be 1g. All you have to do is orient the passenger such that they point in the right direction matching the acceleration and they cannot distinguish this acceleration from that normally experienced on the planet surface.  This is Einstein's equivalence principal.   
The solution hyperloop involves an initial descent phase and final ascent stage, which are connected by the horizontal transport stage.
In an initial descent and final ascent therefore up to 2g could be applied, which is tons; there are more moderate "partly falling" solutions. Generally the shape has to be very carefully calculated.
I'm not saying it's practical, of course, there are enough engineering challenges in hyperloops already, not least of which is maintaining a tube vacuum in the first place.
A: I guess you want to a roller coaster path with constant apparent gravity (in magnitude).  That would be a clothoid loop.

Check the mathematical treatment here.
A: First, 
one should claryfy what it means "to feel acceleration".
If you think of that as being pressed into the back of 
your seat, then yes that can be avoided.
Just fill the passenger cabin with a liquid of similar 
density as your body (e. g. water) and wear some scuba 
apparatus (the cylinders with pressurized air should be 
mounted separately, the tubes from the cylinders to your 
mouth should have a mean density of 1 g cm³)
In such a hyperloop you will see pressure rise and fall 
on a manometer, but no "acceleration" in Your back.
A problem might arise with the cavity of your lung, 
I need to think about that. 
Georg
