You are lying on a beach, your eyes 20 cm above the sand.
Chapter 1, Problem 35(choose chapter or problem)
You are lying on a beach, your eyes 20 cm above the sand. Just as the Sun sets, fully disappearing over the horizon, you immediately jump up, your eyes now 150 cm above the sand, and you can again just see the top of the Sun. If you count the number of seconds until the Sun fully disappears again, you can estimate the Earths radius. But for this Problem, use the known radius of the Earth to calculate the time t.
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