Suppose that, while lying on a beach near the equator of a far-off planet watching the sun set over a calm ocean, you start a stopwatch just as the top of the sun disappears. you then stand, elevating your eyes by a height h = 1.63 m, and stop the watch when the top of the sun again disappears. if the elapsed time is t = 10.1 s, what is the radius r of the planet to two significant figures? notice that duration of a solar day at the far-off planet is the same that is on earth. (hint: see sample problem 1-4.)