##### Question 11.2.9

You’re standing on the shore watching a ship sail away. When it reaches the horizon it starts disappearing due to the curvature of the Earth. Assuming your eyes are $1.5\,\mathrm{m}$ above sea-level and the Earth is a sphere of radius $6,\!400\,\mathrm{km}$, how far away is the horizon (along the straight line between your eyes and the base of the ship)? If you were instead on a cliff, $50\,\mathrm{m}$ above sea-level, how far away would the horizon be then? If you don’t have a calculator, estimate the distance. Show hint