An elevator cabin is at a standstill in non-gravitational field. On the side wall (supposed to be the left wall), there are ten holes (at regular intervals ; vertically). The sun light is coming from the just left and passing through the holes. Then, on the right wall, there are ten projections (spot-lights ; don't move). But, if this elevator cabin begins free fall (downward), projections will move upward.
On the ground, there are slanting rails (45 degrees). On this rails, an elevator cabin was accelerated upward at 1G and then at 2G. Can equivalence principle explain the change of resultant force (by inertial force and gravity) ?
In non-gravitational field, there is a space ship (mother ship). Now, two probes separate from the mother ship and begin an accelerated motion to opposite direction (at 2g and 1g. by gas jet). No gravitational field will occur on the mother ship.
A tall elevator cabin is in free fall. In this cabin, pressure of gaseous body is different (because value g is different). Equivalence principle will be wrong.
An elevator cabin is accelerating upward. With the roof, a small body collided (came vertically). And after 10 seconds, a second body (the same mass) collided (came vertically also). This situation will not be the same to an elevator in gravitational field (at a standstill).
- P.S.- Some books today say that accelerated motion is not relative.
"Accelerated motion is not relative". It’s a subheading of a book (in Japanese). Yes, time dilation in gravitational field is written to be real (one sided ; not relative). But in many books, it seems to be written that "accelerated motion is relative"
