On a large lake without waves, how far from shore is a sailboat when the top of its 7-m mast disappears from the view of a person whose eye height is 1.7 m above the water's edge? Express your answer to three significant figures and include appropriate units.

D = 15.202 km

Explanation:

Given:

- The height of the sail-boat mast below wave h_1 = 7 m

- The level of eyesight above water's edge h_2 = 1.7 m

Find:

how far from shore is a sailboat

Solution:

- The distance from shore (person) to sailboat for a lake with waves is given by the following expression:

D = sqrt (h_1 / 0.0675) + sqrt (h_2 / 0.0675)

Where, D is the curved distance along earth's surface:

- Plug in values and evaluate:

D = sqrt (7 / 0.0675) + sqrt (1.7 / 0.0675)

D = 10.18350 + 5.01848

D = 15.202 km