• Sections
Question on Gravitational Force

# Question on Gravitational Force

Posted in the Physics Forum

First Prev
of 2
Next Last
nakayama

Yokohama, Japan

#21 Mar 12, 2011
There is a small space ship (regard this as an elevator cabin) in free fall. A crew man doesn't feel gravity. But if this space ship is in a non-gravitational field and moves in an accelerated motion (by 1g ; by jet emission), he feels "gravity" 1g (because, external force = gravity acts on every atom directly. but external force = jet emission and its inertial force does not). In short, equivalence principle seems to be wrong.[P.S.] On the ground, gravity acts to the floor. In an accelerated space ship, accelerated force acts from the floor.
nakayama

Yokohama, Japan

#22 Mar 13, 2011
By accelerated motion, no change of gravity will be caused. Change of inertial force only will be caused. If it's true, equivalence principle is wrong.
nakayama

Yokohama, Japan

#23 Mar 15, 2011
On a space station (on every atom), gravity and centrifugal force (an inertial force) is acting independently. Free fall is caused by gravity (not be offset by centrifugal force). In short, equivalence principle seems to be wrong.
nakayama

Yokohama, Japan

#24 Mar 21, 2011
Equivalence principle will be inconsistent with Newton's formula on universal gravitation.
nakayama

Yokohama, Japan

#25 Mar 24, 2011
On a slanting rail (at a 45 degree angle), an elevator cabin is in free fall (without friction). Effect of gravity is obvious. In vertical free fall, it will be the same.
nakayama

Yokohama, Japan

#26 Mar 26, 2011
Imagine gravity and centrifugal force that act on every point of a rotating blade of windmill (zero-weight point occurs instantaneously). Equivalence principle will be wrong.
nakayama

Yokohama, Japan

#27 Apr 23, 2011
On guide rails of elevator, graduations are marked. Momentum (potential energy also) of an elevator cabin in free fall is changing
nakayama

Yokohama, Japan

#28 May 8, 2011
There is a space ship in an accelerated motion (to the above ; non-uniform accelerated motion). A body is hung with an elastic string from the ceiling. Motion of the body will not be the same as the motion caused by the change of gravity (if two bodies are hung with two strings [length is different], it will be more clear).
nakayama

Yokohama, Japan

#29 May 17, 2011
Newton's second law (F = Ma) will stand up on gravity also. And above formula will be meaningful not only on a falling body but also on a body on the ground (differently from a contact force). But in falling and on the ground, how about the value of F and a (g)? Both will be the same. If so, M is the same. Therefore the sameness of gravitational mass and inertial mass will be natural.
nakayama

Yokohama, Japan

#30 May 31, 2011
A windmill (three blades) is rotating. Mass of the blades is the same, but shape is different. So, centrifugal force that acts on the fixed part of the blades is different. How does the equivalence principle explain ?
nakayama

Yokohama, Japan

#31 Jun 5, 2011
There are two elevator cabins. Now one begins free fall. After a few seconds, the other begins free fall also. Motion of the both isn't a uniform motion. How does equivalence principle explain ?
nakayama

Yokohama, Japan

#32 Jun 5, 2011
Relativity seems to be too deified (even Galileo's principle of relativity also). Relativity must be reexamined from its origins (if general relativity is true, even slight curved motion will demand the motion of the universe).
nakayama

Yokohama, Japan

#33 Jun 9, 2011
&#12298;correction&#12 299; Above post (Jun 5 ; Two elevator cabins) was mistake. Both will continue a uniform motion (Relatively). Very sorry.

-To administrator- Please erase above and this posts if it's possible. i am thankful for this forum always.
nakayama

Yokohama, Japan

#34 Jun 10, 2011
In a space elevator, difference of "gravity" (corresponds to the height from the ground) will be explained quantitatively. Equivalence principle will be wrong.
nakayama

Yokohama, Japan

#35 Jun 25, 2011
In the air, an elevator cabin is in "free fall". Eventually, falling speed reaches the terminal speed (at the same time, inertial force fades). This "free fall" will be better (to ascertain the relation between gravity and inertial force) than Einstein's free fall (at least).
nakayama

Yokohama, Japan

#36 Jun 28, 2011
About the equivalence principle ; A little
&#12298;1&#12299; Two small space ships are in free fall. But speed of one of them was decelerated (by jet emission ; downward), and then, was accelerated (by jet emission ; upward) for a while. During the deceleration and acceleration, a crewman (of the latter) would feel -a and a. Equivalence principle will be wrong.
&#12298;2&#12299; Allow me to ask. Are there any error in the following passage (ignore rotary motion). There is a small body. It will be able to ascertain that no external force is acting (except for gravity) on it. So if there is some internal force, it's caused by gravity !! Equivalence principle will be wrong.
nakayama

Yokohama, Japan

#37 Nov 25, 2011
Allow me to ask please. If distance to the sun is shorter, "difference above (Jan 10, 2011)" seems to be detectable easily.
nakayama

Yokohama, Japan

#38 Nov 26, 2011
Im sorry. Yesterdays post is wrong.

nakayama

Yokohama, Japan

#39 Nov 28, 2011
P.S. to post (Jan 10 2011)

Suppose that speed of propagation of gravity is the same to light speed and propagation follows aether frame (like light-time correction). If so, its conceivable that because of the motion of the solar system, direction of gravity (at the earths surface) deviates from the center of gravity of the earth (and direction of deviation changes because of rotation of the earth). If speed of the solar system is 400km/sec, deviation is under a 0.2degree angle (at maximum). It may be detectable.

#### Tell me when this thread is updated:

Subscribe Now Add to my Tracker
First Prev
of 2
Next Last

Characters left: 4000

Please note by submitting this form you acknowledge that you have read the Terms of Service and the comment you are posting is in compliance with such terms. Be polite. Inappropriate posts may be removed by the moderator. Send us your feedback.

### Physics Discussions

Speed Of Light May Not Be Constant After All, P... (May '13) 14 min nakayama 92
Serway College Physics 9th ed TEST BANK NEEDED!!! (May '11) Oct 22 Chase 27
Baseball vs Tennis Ball (Jan '07) Oct 22 Guest 18
Where is Lorenz contraction ? (Dec '15) Oct 21 nakayama 56
About Time Dilation (Oct '10) Oct 7 nakayama 35
What is Absolute Zero? Oct 6 chugs vote Liberal 10
Weird science: 3 win Nobel physics prize for un... Oct 5 Cromagnon Man 5

#### Physics News

More Physics News from Topix »

More from around the web