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0 pointsdrdeca5y ago0 comments

First, "it all adds up to normality". Second, hm, I'm not sure. Well, the glass on the table next to me is "accelerating", but in my frame of reference (which is the same as that of the glass) it is also stationary...?

If I drop a ball above the glass, and we consider things from the frame of reference where the ball is stationary, which (neglecting air resistance) is an inertial reference frame. In this frame, the glass is accelerating ball-wards , because of the table pushing on it, and, this force is applied over a distance as the glass approaches the ball. So, yes, it seems that the KE of the glass should be increasing in the reference frame of the ball.

Hm, I'm confused.

I suppose if we consider a geodesic representing a periodic orbit around the earth, that the positions and velocities of various objects on earth will be in a cyclic pattern?

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colordrops5y ago

The layman descriptions are probably incomplete or rough abstractions missing nuance. Reminds me of the idea of a rubber membrane with balls on it representing the curvature of spacetime explaining how gravity works - I've always disliked that example because you still need plain old gravity to pull the balls into the membrane.

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colordrops5y ago

j / k navigate · click thread line to collapse