100 Year Marathon

To rewind this description, in his finding gravity is indistinguishable from acceleration. To give a very quick recap of this conceptual idea. Figure 3 above is showing a person in a box throwing a ball forward. It goes to the ground of the box. The physical effect at play, as to why the ball is going to the ground will be already moving into the second part of the explanation of his theory. What young Albert was pondering for some years, if there would be any difference that can be proven in the two following cases, shown in Figure 4 below: