theres a problem in wheeler's spacetime physics (exercise 2-9) which goes like this : you are in a horizontal railway coach launched upwards from the surface of the earth. there are two ball bearing at opposite ends of the coach. can you distinguish whether the coach is rising or falling by observing the ball bearings from inside the coach? so this is what i thought : there will be tidal acceleration between the two ball bearings the whole time during the free fall since the gravitational field is not perfectly uniform. the further away you are from the earth, the smaller the tidal accelerations will be. so as you are rising, you will be able to observe that the tidal accelerations decrese, reach a minimum at the top, and increase again as you fall back to the earth. so we must be able to tell whether we are rising or falling. the answer at the back of the book says that you cant distinguish between rising and falling by observing the ball bearings. where did i go wrong?